1
|
Serwatka T, Yim S, Ayotte P, Roy PN. On the nature of the Schottky anomaly in endohedral water. J Chem Phys 2023; 158:124310. [PMID: 37003742 DOI: 10.1063/5.0148882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
In this work, we study the heat capacity contribution of a rigid water molecule encapsulated in C60 by performing six-dimensional eigenstate calculations with the inclusion of its quantized rotational and translational degrees of freedom. Two confinement model potentials are considered: in the first, confinement is described using distributed pairwise Lennard-Jones interactions, while in the second, the water molecule is trapped within an eccentric but isotropic 3D harmonic effective confinement potential [Wespiser et al., J. Chem. Phys. 156, 074304 (2022)]. Contributions to the heat capacity from both the ortho and para nuclear spin isomers of water are considered to enable the effects of their interconversion to be assessed. By including a symmetry-breaking quadrupolar potential energy term in the Hamiltonian, we can reproduce the experimentally observed Schottky anomaly at ∼2 K [Suzuki et al., J. Phys. Chem. Lett. 10, 1306 (2019)]. Furthermore, our calculations predict a second Schottky anomaly at ∼0.1 K resulting from the H configuration, a different orientational arrangement of the fullerene cages in crystalline solid C60. Contributions from the H configuration to CV also explain the second peak observed at ∼7 K in the experimentally measured heat capacity.
Collapse
Affiliation(s)
- Tobias Serwatka
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Spencer Yim
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| |
Collapse
|
2
|
Rademacher J, Reedy ES, Negri F, Alom S, Whitby RJ, Levitt MH, Campbell EK. Gas-phase electronic spectroscopy of nuclear spin isomer separated H 2O@C and D 2O@C. Mol Phys 2023. [DOI: 10.1080/00268976.2023.2173507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
| | | | - Fabrizia Negri
- Dipartimento di Chimica ‘Giacomo Ciamician’ and INSTM, Università di Bologna, Bologna, Italy
| | - Shamim Alom
- Chemistry, University of Southampton, Southampton, Hants, UK
| | | | | | | |
Collapse
|
3
|
Jafari T, Razvan Bacanu G, Shugai A, Nagel U, Walkey M, Hoffman G, Levitt MH, Whitby RJ, Rõõm T. Terahertz spectroscopy of the helium endofullerene He@C 60. Phys Chem Chem Phys 2022; 24:9943-9952. [PMID: 35445229 DOI: 10.1039/d2cp00515h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We studied the quantized translational motion of single He atoms encapsulated in molecular cages by terahertz absorption. The temperature dependence of the THz absorption spectra of 3He@C60 and 4He@C60 crystal powder samples was measured between 5 and 220 K. At 5 K there is an absorption line at 96.8 cm-1 (2.90 THz) in 3He@C60 and at 81.4 cm (2.44 THz) in 4He@C60, while additional absorption lines appear at higher temperature. An anharmonic spherical oscillator model with a displacement-induced dipole moment was used to model the absorption spectra. Potential energy terms with powers of two, four and six and induced dipole moment terms with powers one and three in the helium atom displacement from the fullerene cage center were sufficient to describe the experimental results. Excellent agreement is found between potential energy functions derived from measurements on the 3He and 4He isotopes. One absorption line corresponds to a three-quantum transition in 4He@C60, allowed by the anharmonicity of the potential function and by the non-linearity of the dipole moment in He atom displacement. The potential energy function of icosahedral symmetry does not explain the fine structure observed in the low temperature spectra.
Collapse
Affiliation(s)
- Tanzeeha Jafari
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | | | - Anna Shugai
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Urmas Nagel
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Mark Walkey
- School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
| | - Gabriela Hoffman
- School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
| | - Richard J Whitby
- School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
| | - Toomas Rõõm
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| |
Collapse
|
4
|
Xu M, Felker PM, Bačić Z. H 2O inside the fullerene C 60: Inelastic neutron scattering spectrum from rigorous quantum calculations. J Chem Phys 2022; 156:124101. [PMID: 35364860 DOI: 10.1063/5.0086842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a methodology that, for the first time, allows rigorous quantum calculation of the inelastic neutron scattering (INS) spectra of a triatomic molecule in a nanoscale cavity, in this case, H2O inside the fullerene C60. Both moieties are taken to be rigid. Our treatment incorporates the quantum six-dimensional translation-rotation (TR) wave functions of the encapsulated H2O, which serve as the spatial parts of the initial and final states of the INS transitions. As a result, the simulated INS spectra reflect the coupled TR dynamics of the nanoconfined guest molecule. They also exhibit the features arising from symmetry breaking observed for solid H2O@C60 at low temperatures. Utilizing this methodology, we compute the INS spectra of H2O@C60 for two incident neutron wavelengths and compare them with the corresponding experimental spectra. Good overall agreement is found, and the calculated spectra provide valuable additional insights.
Collapse
Affiliation(s)
- Minzhong Xu
- Department of Chemistry, New York University, New York, New York 10003, USA
| | - Peter M Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
| |
Collapse
|
5
|
Carrillo-Bohórquez O, Valdés Á, Prosmiti R. Unraveling the Origin of Symmetry Breaking in H 2 O@C 60 Endofullerene Through Quantum Computations. Chemphyschem 2022; 23:e202200034. [PMID: 35289042 PMCID: PMC9311847 DOI: 10.1002/cphc.202200034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/01/2022] [Indexed: 11/09/2022]
Abstract
We explore the origin of the anomalous splitting of the 101 levels reported experimentally for the H2O@C60 endofullerene, in order to give some insight about the physical interpretations of the symmetry breaking observed. We performed fully‐coupled quantum computations within the multiconfiguration time‐dependent Hartree approach employing a rigorous procedure to handle such computationally challenging problems. We introduce two competing physical models, and discuss the observed unconventional quantum patterns in terms of anisotropy in the interfullerene interactions, caused by the change in the off‐center position of the encapsulated water molecules inside the cage or the uniaxial C60‐cage distortion, arising from noncovalent bonding upon water's encapsulation, or exohedral fullerene perturbations. Our results show that both scenarios could reproduce the experimentally observed rotational degeneracy pattern, although quantitative agreement with the available experimental rotational levels splitting value has been achieved by the model that considers an uniaxial elongation of the C60‐cage. Such finding supports that the observed symmetry breaking could be mainly caused by the distortion of the fullerene cage. However, as nuclear quantum treatments rely on the underlying interactions, a decisive conclusion hinges on the availability of their improved description, taken into account both endofullerene and exohedral environments, from forthcoming highly demanding electronic structure many‐body interaction studies.
Collapse
Affiliation(s)
- Orlando Carrillo-Bohórquez
- Institute of Fundamental Physics (IFF-CSIC), CSIC, Serrano 123, 28006, Madrid, Spain.,Departamento de Física, Universidad Nacional de Colombia, Calle 26, Cra 39, Edificio 404, Bogotá, Colombia
| | - Álvaro Valdés
- Escuela de Física, Universidad Nacional de Colombia, Sede Medellín, A. A. 3840, Medellín, Colombia
| | - Rita Prosmiti
- Institute of Fundamental Physics (IFF-CSIC), CSIC, Serrano 123, 28006, Madrid, Spain
| |
Collapse
|
6
|
Wespiser C, Putaud T, Kalugina YN, Soldera A, Roy PN, Michaut X, Ayotte P. Ro-translational dynamics of confined water: I - The confined asymmetric rotor model. J Chem Phys 2022; 156:074304. [DOI: 10.1063/5.0079565] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Thomas Putaud
- Universite de Sherbrooke Departement de chimie, Canada
| | | | - Armand Soldera
- Department of Chemistry, Universite de Sherbrooke, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo Department of Chemistry, Canada
| | | | - Patrick Ayotte
- Département de Chimie, Universite de Sherbrooke Departement de chimie, Canada
| |
Collapse
|
7
|
Putaud T, Wespiser C, Bertin M, Fillion JH, Kalugina YN, Jeseck P, Milpanis A, Philippe L, Soulard P, Tremblay B, Tuloup C, Ayotte P, Michaut X. Ro-translational dynamics of confined water: II - Spectroscopic evidence of confinement effects on the far-infrared spectra of water isotopologues in argon and krypton matrices. J Chem Phys 2022; 156:074305. [DOI: 10.1063/5.0079566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas Putaud
- Universite de Sherbrooke Departement de chimie, Canada
| | | | | | | | | | | | | | | | | | | | | | - Patrick Ayotte
- Département de Chimie, Universite de Sherbrooke Departement de chimie, Canada
| | | |
Collapse
|
8
|
Felker PM, Bačić Z. Noncovalently bound molecular complexes beyond diatom–diatom systems: full-dimensional, fully coupled quantum calculations of rovibrational states. Phys Chem Chem Phys 2022; 24:24655-24676. [DOI: 10.1039/d2cp04005k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The methodological advances made in recent years have significantly extended the range and dimensionality of noncovalently bound molecular complexes for which full-dimensional quantum calculations of their rovibrational states are feasible.
Collapse
Affiliation(s)
- Peter M. Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, NY, 10003, USA
- Simons Center for Computational Physical Chemistry at New York University, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai, 200062, China
| |
Collapse
|
9
|
Du S, Hashikawa Y, Ito H, Hashimoto K, Murata Y, Hirayama Y, Hirakawa K. Inelastic Electron Transport and Ortho-Para Fluctuation of Water Molecule in H 2O@C 60 Single Molecule Transistors. NANO LETTERS 2021; 21:10346-10353. [PMID: 34854686 DOI: 10.1021/acs.nanolett.1c03604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Light molecules such as H2O are the systems in which we can have access to quantum mechanical information on their constituent atoms. Here, we have investigated electron transport through H2O@C60 single molecule transistors (SMTs). The H2O@C60 SMTs exhibit Coulomb stability diagrams that show multiple tunneling-induced excited states below 30 meV. Furthermore, we have performed terahertz (THz) photocurrent spectroscopy on H2O@C60 SMTs and confirmed the same excitations. From comparison between experiment and theory, the excitations observed below 10 meV are identified to be the quantum rotational excitations of the water molecule. Surprisingly, the quantum rotational excitations of both para- and ortho-water molecule are observed simultaneously even for a single water molecule, indicating that the fluctuation between the ortho- and para-water states takes place in a time scale shorter than our measurement time (∼1 min), probably by the interaction between the encapsulated water molecule and conducting electrons.
Collapse
Affiliation(s)
- Shaoqing Du
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Yoshifumi Hashikawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Haruka Ito
- Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Katsushi Hashimoto
- Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
- Centre for Spintronics Research Network, Tohoku University, Sendai 980-8578, Japan
- Center for Science and Innovation in Spintronics (Core Research Cluster), Tohoku University, Sendai 980-8577, Japan
| | - Yasujiro Murata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yoshiro Hirayama
- Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
- Centre for Spintronics Research Network, Tohoku University, Sendai 980-8578, Japan
- Center for Science and Innovation in Spintronics (Core Research Cluster), Tohoku University, Sendai 980-8577, Japan
| | - Kazuhiko Hirakawa
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| |
Collapse
|
10
|
Dolgonos GA. Exploring the Properties of H
2
O@C
60
with the Local Second‐Order Møller‐Plesset Perturbation Theory: Blue or Red Shift in C
60
and H
2
O Fundamentals to Expect? ChemistrySelect 2021. [DOI: 10.1002/slct.202103004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Grygoriy A. Dolgonos
- Institute of Chemistry University of Graz Heinrichstrasse 28/IV A-8010 Graz Austria
- Life Chemicals Inc. Murmanska Str. 5 02660 Kyiv Ukraine
| |
Collapse
|
11
|
Carrillo-Bohórquez O, Valdés Á, Prosmiti R. Encapsulation of a Water Molecule inside C 60 Fullerene: The Impact of Confinement on Quantum Features. J Chem Theory Comput 2021; 17:5839-5848. [PMID: 34420292 PMCID: PMC8444341 DOI: 10.1021/acs.jctc.1c00662] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
We introduce an efficient
quantum fully coupled computational scheme
within the multiconfiguration time-dependent Hartree (MCTDH) approach
to handle the otherwise extremely costly computations of translational–rotational–vibrational
states and energies of light-molecule endofullenes. Quantum calculations
on energy levels are reported for a water molecule inside C60 fullerene by means of such a systematic approach that includes all
nine degrees of freedom of H2O@C60 and does
not consider restrictions above them. The potential energy operator
is represented as a sum of natural potentials employing the n-mode expansion, along with the exact kinetic energy operator,
by introducing a set of Radau internal coordinates for the H2O molecule. On the basis of the present rigorous computations, various
aspects of the quantized intermolecular dynamics upon confinement
of H2O@C60 are discussed, such as the rotational
energy level splitting and the significant frequency shifts of the
encapsulated water molecule vibrations. The impact of water encapsulation
on quantum features is explored, and insights into the nature of the
underlying forces are provided, highlighting the importance of a reliable
first-principles description of the guest–host interactions.
Collapse
Affiliation(s)
- Orlando Carrillo-Bohórquez
- Departamento de Física, Universidad Nacional de Colombia, Calle 26, Cra 39, 404 Edificio, Bogotá, Colombia.,Institute of Fundamental Physics (IFF-CSIC), CSIC, Serrano 123, 28006 Madrid, Spain
| | - Álvaro Valdés
- Escuela de Física, Universidad Nacional de Colombia, Sede Medellín, A. A 3840 Medellín, Colombia
| | - Rita Prosmiti
- Institute of Fundamental Physics (IFF-CSIC), CSIC, Serrano 123, 28006 Madrid, Spain
| |
Collapse
|
12
|
Horii Y, Suzuki H, Miyazaki Y, Nakano M, Hasegawa S, Hashikawa Y, Murata Y. Dynamics and magnetic properties of NO molecules encapsulated in open-cage fullerene derivatives evidenced by low temperature heat capacity. Phys Chem Chem Phys 2021; 23:10251-10256. [PMID: 33899869 DOI: 10.1039/d1cp00482d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Low-temperature heat capacity analyses for an NO-encapsulated fullerene derivative revealed (i) low-energy motion and (ii) strong magnetic anisotropy of the NO molecule due to its orbital angular momentum. The low-energy motion was attributed to reorientational motions of the NO molecules, in which only a small number (n ∼ 0.04) of NO molecules were found to participate. The NO molecules were confirmed to be paramagnetic even at 1 K. Ab-initio calculation indicated that the magnetic properties of the NO unit strongly depended on its surroundings, allowing the conformation of the fullerene cage to be estimated.
Collapse
Affiliation(s)
- Yoji Horii
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Hal Suzuki
- Department of Chemistry, Kindai University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Yuji Miyazaki
- Research Center for Thermal and Entropic Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Motohiro Nakano
- Research Center for Thermal and Entropic Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Shota Hasegawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yoshifumi Hashikawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yasujiro Murata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| |
Collapse
|
13
|
Shugai A, Nagel U, Murata Y, Li Y, Mamone S, Krachmalnicoff A, Alom S, Whitby RJ, Levitt MH, Rõõm T. Infrared spectroscopy of an endohedral water in fullerene. J Chem Phys 2021; 154:124311. [PMID: 33810704 DOI: 10.1063/5.0047350] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An infrared absorption spectroscopy study of the endohedral water molecule in a solid mixture of H2O@C60 and C60 was carried out at liquid helium temperature. From the evolution of the spectra during the ortho-para conversion process, the spectral lines were identified as para-H2O and ortho-H2O transitions. Eight vibrational transitions with rotational side peaks were observed in the mid-infrared: ω1, ω2, ω3, 2ω1, 2ω2, ω1 + ω3, ω2 + ω3, and 2ω2 + ω3. The vibrational frequencies ω2 and 2ω2 are lower by 1.6% and the rest by 2.4%, as compared to those of free H2O. A model consisting of a rovibrational Hamiltonian with the dipole and quadrupole moments of H2O interacting with the crystal field was used to fit the infrared absorption spectra. The electric quadrupole interaction with the crystal field lifts the degeneracy of the rotational levels. The finite amplitudes of the pure v1 and v2 vibrational transitions are consistent with the interaction of the water molecule dipole moment with a lattice-induced electric field. The permanent dipole moment of encapsulated H2O is found to be 0.50 ± 0.05 D as determined from the far-infrared rotational line intensities. The translational mode of the quantized center-of-mass motion of H2O in the molecular cage of C60 was observed at 110 cm-1 (13.6 meV).
Collapse
Affiliation(s)
- A Shugai
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - U Nagel
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - Y Murata
- Institute for Chemical Research, Kyoto University, Kyoto 611-0011, Japan
| | - Yongjun Li
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - S Mamone
- School of Chemistry, Southampton University, Southampton SO17 1BJ, United Kingdom
| | - A Krachmalnicoff
- School of Chemistry, Southampton University, Southampton SO17 1BJ, United Kingdom
| | - S Alom
- School of Chemistry, Southampton University, Southampton SO17 1BJ, United Kingdom
| | - R J Whitby
- School of Chemistry, Southampton University, Southampton SO17 1BJ, United Kingdom
| | - M H Levitt
- School of Chemistry, Southampton University, Southampton SO17 1BJ, United Kingdom
| | - T Rõõm
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| |
Collapse
|
14
|
Hashikawa Y, Kizaki K, Murata Y. Pressure-induced annulative orifice closure of a cage-opened C 60 derivative. Chem Commun (Camb) 2021; 57:5322-5325. [PMID: 33928322 DOI: 10.1039/d1cc01662h] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A cage-opened C60 derivative was found to undergo an unusual annulative orifice-closure reaction under high-pressure conditions, in which the orifice size changed from a 16- to a 13-membered ring. The structure was different from that obtained by the reaction at 1 atm. The theoretical calculations suggested that the formation of the former one is thermodynamically favored.
Collapse
Affiliation(s)
- Yoshifumi Hashikawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Kazuro Kizaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yasujiro Murata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| |
Collapse
|
15
|
Zhukov SS, Balos V, Hoffman G, Alom S, Belyanchikov M, Nebioglu M, Roh S, Pronin A, Bacanu GR, Abramov P, Wolf M, Dressel M, Levitt MH, Whitby RJ, Gorshunov B, Sajadi M. Rotational coherence of encapsulated ortho and para water in fullerene-C 60 revealed by time-domain terahertz spectroscopy. Sci Rep 2020; 10:18329. [PMID: 33110105 PMCID: PMC7592058 DOI: 10.1038/s41598-020-74972-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/06/2020] [Indexed: 11/15/2022] Open
Abstract
We resolve the real-time coherent rotational motion of isolated water molecules encapsulated in fullerene-C60 cages by time-domain terahertz (THz) spectroscopy. We employ single-cycle THz pulses to excite the low-frequency rotational motion of water and measure the subsequent coherent emission of electromagnetic waves by water molecules. At temperatures below ~ 100 K, C60 lattice vibrational damping is mitigated and the quantum dynamics of confined water are resolved with a markedly long rotational coherence, extended beyond 10 ps. The observed rotational transitions agree well with low-frequency rotational dynamics of single water molecules in the gas phase. However, some additional spectral features with their major contribution at ~2.26 THz are also observed which may indicate interaction between water rotation and the C60 lattice phonons. We also resolve the real-time change of the emission pattern of water after a sudden cooling to 4 K, signifying the conversion of ortho-water to para-water over the course of 10s hours. The observed long coherent rotational dynamics of isolated water molecules confined in C60 makes this system an attractive candidate for future quantum technology.
Collapse
Affiliation(s)
| | | | | | - Shamim Alom
- School of Chemistry, University of Southampton, Southampton, UK
| | | | - Mehmet Nebioglu
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - Seulki Roh
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - Artem Pronin
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - George R Bacanu
- School of Chemistry, University of Southampton, Southampton, UK
| | - Pavel Abramov
- Moscow Institute of Physics and Technology, Moscow, Russia
| | - Martin Wolf
- Fritz-Haber-Institut der MPG, Berlin, Germany
| | - Martin Dressel
- Moscow Institute of Physics and Technology, Moscow, Russia
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | | | | | | | - Mohsen Sajadi
- Fritz-Haber-Institut der MPG, Berlin, Germany.
- Department of Chemistry, University of Paderborn, Paderborn, Germany.
| |
Collapse
|
16
|
Xu M, Felker PM, Bačić Z. Light molecules inside the nanocavities of fullerenes and clathrate hydrates: inelastic neutron scattering spectra and the unexpected selection rule from rigorous quantum simulations. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1794097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Minzhong Xu
- Department of Chemistry, New York University, New York, NY, USA
| | - Peter M. Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, NY, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, People's Republic of China
| |
Collapse
|
17
|
Li J, Xu Q, Sun L, Xu J, Hao D, Tang X, Shan X, Meng S, Lu X. Rotational and Vibrational Excitations of a Single Water Molecule by Inelastic Electron Tunneling Spectroscopy. J Phys Chem Lett 2020; 11:1650-1655. [PMID: 32039599 DOI: 10.1021/acs.jpclett.0c00093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two low-energy excitations of a single water molecule are observed via inelastic electron tunneling spectroscopy, where a significant enhancement is achieved by attaching the molecule to the tip apex in a scanning tunneling microscope. Density functional theory simulations and quantum mechanical calculations of an asymmetric top are carried out to reveal the origin of both excitations. Variations in tunneling junction separation give rise to the quantum confinement effect on the quantum state of a water molecule in the tunneling junction. Our results demonstrate a potential method for measuring the dynamic behavior of a single molecule confined in a tunneling junction, where the molecule-substrate interaction can be purposely tuned.
Collapse
Affiliation(s)
- Jianmei Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Qiuhao Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Lihuan Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jiyu Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Dong Hao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xiangqian Tang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xinyan Shan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Laboratory for Materials Science, Dongguan, Guangdong 523000, China
| | - Xinghua Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Center for Excellence in Topological Quantum Computation, Beijing 100190, China
- Songshan Lake Laboratory for Materials Science, Dongguan, Guangdong 523000, China
| |
Collapse
|
18
|
Felker PM, Bačić Z. Flexible water molecule in C60: Intramolecular vibrational frequencies and translation-rotation eigenstates from fully coupled nine-dimensional quantum calculations with small basis sets. J Chem Phys 2020; 152:014108. [DOI: 10.1063/1.5138992] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Peter M. Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062, China
| |
Collapse
|
19
|
Xu M, Felker PM, Mamone S, Horsewill AJ, Rols S, Whitby RJ, Bačić Z. The Endofullerene HF@C 60: Inelastic Neutron Scattering Spectra from Quantum Simulations and Experiment, Validity of the Selection Rule, and Symmetry Breaking. J Phys Chem Lett 2019; 10:5365-5371. [PMID: 31454486 DOI: 10.1021/acs.jpclett.9b02005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Accurate quantum simulations of the low-temperature inelastic neutron scattering (INS) spectra of HF@C60 are reported for two incident neutron wavelengths. They are distinguished by the rigorous inclusion of symmetry-breaking effects in the treatment and having the spectra computed with HF as the guest, rather than H2 or HD, as in the past work. The results demonstrate that the precedent-setting INS selection rule, originally derived for H2 and HD in near-spherical nanocavities, applies also to HF@C60, despite the large mass asymmetry of HF and the strongly mixed character of its translation-rotation eigenstates. This lends crucial support to the theoretical prediction made earlier that the INS selection rule is valid for any diatomic molecule in near-spherical nanoconfinement. The selection rule remains valid in the presence of symmetry breaking but is modified slightly in an interesting way. Comparison is made with the recently published experimental INS spectrum of HF@C60. The agreement is very good, apart from one peak for which our calculations suggest a reassignment. This reassignment is consistent with the measured INS spectrum presented in this work, which covers an extended energy range.
Collapse
Affiliation(s)
- Minzhong Xu
- Department of Chemistry , New York University , New York , New York 10003 , United States
| | - Peter M Felker
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095-1569 , United States
| | - Salvatore Mamone
- School of Physics & Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Anthony J Horsewill
- School of Physics & Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Stéphane Rols
- Institut Laue-Langevin , CS 20156, 38042 Grenoble , France
| | - Richard J Whitby
- Chemistry, Faculty of Engineering and Physical Sciences , University of Southampton , Southampton SO17 1BJ , United Kingdom
| | - Zlatko Bačić
- Department of Chemistry , New York University , New York , New York 10003 , United States
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai , 3663 Zhongshan Road North , Shanghai 200062 , China
| |
Collapse
|
20
|
Hashikawa Y, Murata Y. H2O/Olefinic-π Interaction inside a Carbon Nanocage. J Am Chem Soc 2019; 141:12928-12938. [DOI: 10.1021/jacs.9b06759] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yoshifumi Hashikawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yasujiro Murata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| |
Collapse
|
21
|
Kolesnikov AI, Anovitz LM, Hawthorne FC, Podlesnyak A, Schenter GK. Effect of fine-tuning pore structures on the dynamics of confined water. J Chem Phys 2019; 150:204706. [DOI: 10.1063/1.5096771] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. I. Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L. M. Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - F. C. Hawthorne
- Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G. K. Schenter
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 93352, USA
| |
Collapse
|
22
|
Suzuki H, Nakano M, Hashikawa Y, Murata Y. Rotational Motion and Nuclear Spin Interconversion of H 2O Encapsulated in C 60 Appearing in the Low-Temperature Heat Capacity. J Phys Chem Lett 2019; 10:1306-1311. [PMID: 30835479 DOI: 10.1021/acs.jpclett.9b00311] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The heat capacity of H2O encapsulated in fullerene C60 is determined for the first time at temperatures between 0.6 and 200 K. The water molecule in H2O@C60 undergoes quantum rotation at low temperature, and the ortho-H2O and para-H2O isomers are identified by labeling the rotational energy levels with the nuclear spin states. A rounded heat capacity maximum is observed at ∼2 K after rapid cooling due to splitting of the rotational J KaKc = 101 ground state of ortho-H2O. This anomalous feature decreases in magnitude over time, reflecting the conversion of ortho-H2O to para-H2O. Time-dependent heat capacity measurements at constant temperature reveal three nuclear spin conversion processes: a thermally activated transition with Ea ≈ 3.2 meV and two temperature-independent tunneling processes with time constants of τ1 ≈ 1.5 h and τ2 ≈ 11 h.
Collapse
Affiliation(s)
- Hal Suzuki
- Department of Chemistry , Kindai University , 3-4-1 Kowakae , Higashiosaka , Osaka 577-8502 , Japan
| | - Motohiro Nakano
- Research Center for Structural Thermodynamics, Graduate School of Science , Osaka University , 1-1 Machikaneyama-cho , Toyonaka , Osaka 560-0043 , Japan
| | - Yoshifumi Hashikawa
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Yasujiro Murata
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| |
Collapse
|
23
|
Rashed E, Dunn JL. Interactions between a water molecule and C 60 in the endohedral fullerene H 2O@C 60. Phys Chem Chem Phys 2019; 21:3347-3359. [PMID: 30688323 DOI: 10.1039/c8cp04390f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A water molecule encapsulated inside a C60 fullerene cage behaves almost like an asymmetric top rotor, as would be expected of an isolated water molecule. However, inelastic neutron scattering (INS) experiments show evidence of interactions between the water molecule and its environment [Goh et al., Phys. Chem. Chem. Phys., 2014, 16, 21330]. In particular, a resolved splitting of the 101 rotational level into a singlet and a doublet indicates that the water molecule experiences an environment of lower symmetry than the icosahedral symmetry of a C60 cage. Recent calculations have shown that the splitting can be explained in terms of electrostatic quadrupolar interactions between the water molecule and the electron clouds of nearest-neighbour C60 molecules, which results in an effective environment of S6 symmetry [Felker et al., Phys. Chem. Chem. Phys., 2017, 19, 31274 and Bačić et al., Faraday Discussions, 2018, 212, 547-567]. We use symmetry arguments to obtain a simple algebraic expression, expressed in terms of a linear combination of products of translational and rotational basis functions, that describes the effect on a water molecule of any potential of S6 symmetry. We show that we can reproduce the results of the electrostatic interaction model up to ≈12 meV in terms of two unknown parameters only. The resulting potential is in a form that can readily be used in future calculations, without needing to use density functional theory (DFT) for example. Adjusting parameters in our potential would help identify whether other symmetry-lowering interactions are also present if experimental results that resolve splittings in higher-energy rotational levels are obtained in the future. As another application of our model, we show that the results of DFT calculations of the variation in energy as a water molecule moves inside the cage of an isolated C60 molecule, where the water molecule experiences an environment of icosahedral symmetry, can also be reproduced using our model.
Collapse
Affiliation(s)
- Effat Rashed
- School of Physics & Astronomy, University Park, Nottingham, UK.
| | | |
Collapse
|
24
|
Bačić Z, Vlček V, Neuhauser D, Felker PM. Effects of symmetry breaking on the translation-rotation eigenstates of H 2, HF, and H 2O inside the fullerene C 60. Faraday Discuss 2018; 212:547-567. [PMID: 30226507 DOI: 10.1039/c8fd00082d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Splittings of the translation-rotation (TR) eigenstates of the solid light-molecule endofullerenes M@C60 (M = H2, H2O, HF) attributed to the symmetry breaking have been observed in the infrared (IR) and inelastic neutron scattering spectra of these species in the past couple of years. In a recent paper [Felker et al., Phys. Chem. Chem. Phys., 2017, 19, 31274], we established that the electrostatic, quadrupolar interaction between the guest molecule M and the twelve nearest-neighbor C60 cages of the solid is the main source of the symmetry breaking. The splittings of the three-fold degenerate ground states of the endohedral ortho-H2, ortho-H2O and the j = 1 level of HF calculated using this model were found to be in excellent agreement with the experimental results. Utilizing the same electrostatic model, this theoretical study investigates the effects of the symmetry breaking on the excited TR eigenstates of the three species, and how they manifest in their simulated low-temperature (5-6 K) near-IR (NIR) and far-IR (FIR) spectra. The TR eigenstates are calculated variationally for both the major P and minor H crystal orientations. For the H orientation, the calculated splittings of all of the TR levels of these species are less than 0.1 cm-1. For the dominant P orientation, the splittings vary strongly depending on the character of the excitations involved. In all of the species, the splittings of the higher rotationally excited levels are comparable in magnitude to those for the j = 1 levels. For the levels corresponding to purely translational excitations, the calculated splittings are about an order of magnitude smaller than those of the purely rotational eigenstates. Based on the computed TR eigenstates, the low-temperature NIR (for M = H2) and FIR (for M = HF and H2O) spectra are simulated for both the P and H orientations, and also combined as their weighted sum (0.15H + 0.85P). The weighted sum spectra computed for M = H2 and HF match quantitatively the corresponding measured spectra, while for M = H2O, the weighted sum FIR spectrum predicts features that can potentially be observed experimentally.
Collapse
Affiliation(s)
- Zlatko Bačić
- Department of Chemistry, New York University, New York, NY 10003, USA. and NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai, 200062, China
| | - Vojtěch Vlček
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
| | - Daniel Neuhauser
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
| | - Peter M Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
| |
Collapse
|
25
|
Valdés Á, Carrillo-Bohórquez O, Prosmiti R. Fully Coupled Quantum Treatment of Nanoconfined Systems: A Water Molecule inside a Fullerene C 60. J Chem Theory Comput 2018; 14:6521-6531. [PMID: 30419169 DOI: 10.1021/acs.jctc.8b00801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We implemented a systematic procedure for treating the quantal rotations by including all translational and vibrational degrees of freedom for any triatomic bent molecule in any embedded or confined environment, within the MCTDH framework. Fully coupled quantum treatments were employed to investigate unconventional properties in nanoconfined molecular systems. In this way, we facilitate a complete theoretical analysis of the underlying dynamics that enables us to compute the energy levels and the nuclear spin isomers of a single water molecule trapped in a C60 fullerene cage. The key point lies in the full 9D description of both nuclear and electronic degrees of freedom, as well as a reliable representation of the guest-host interaction. The presence of occluded impurities or inhomogeneities due to noncovalent interactions in the interfullerene environment could modify aspects of the potential, causing significant coupling between otherwise uncoupled modes. Using specific n-mode model potentials, we obtained splitting patterns that confirm the effects of symmetry breaking observed by experiments in the ground ortho-H2O state. Further, our investigation reveals that the first rotationally excited states of the encapsulated ortho- and para-H2O have also raised their 3-fold degeneracy. In view of the complexity of the problem, our results highlight the importance of accurate and computational demanding approaches for building up predictive models for such nanoconfined molecules.
Collapse
Affiliation(s)
- Álvaro Valdés
- Departamento de Física , Universidad Nacional de Colombia , Calle 26, Cra 39, Edicio 404 , Bogotá , Colombia
| | - Orlando Carrillo-Bohórquez
- Departamento de Física , Universidad Nacional de Colombia , Calle 26, Cra 39, Edicio 404 , Bogotá , Colombia
| | - Rita Prosmiti
- Institute of Fundamental Physics (IFF-CSIC), CSIC , Serrano 123 , 28006 Madrid , Spain
| |
Collapse
|
26
|
Bačić Z. Perspective: Accurate treatment of the quantum dynamics of light molecules inside fullerene cages: Translation-rotation states, spectroscopy, and symmetry breaking. J Chem Phys 2018; 149:100901. [PMID: 30219006 DOI: 10.1063/1.5049358] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In this perspective, I review the current status of the theoretical investigations of the quantum translation-rotation (TR) dynamics and spectroscopy of light molecules encapsulated inside fullerenes, mostly C60 and C70. The methodologies developed in the past decade allow accurate quantum calculations of the TR eigenstates of one and two nanoconfined molecules and have led to deep insights into the nature of the underlying dynamics. Combining these bound-state methodologies with the formalism of inelastic neutron scattering (INS) has resulted in the novel and powerful approach for the quantum calculation of the INS spectra of a diatomic molecule in a nanocavity with an arbitrary geometry. These simulations have not only become indispensable for the interpretation and assignment of the experimental spectra but are also behind the surprising discovery of the INS selection rule for diatomics in near-spherical nanocavities. Promising directions for future research are discussed.
Collapse
Affiliation(s)
- Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
| |
Collapse
|
27
|
Zhu GZ, Liu Y, Hashikawa Y, Zhang QF, Murata Y, Wang LS. Probing the interaction between the encapsulated water molecule and the fullerene cages in H 2O@C 60- and H 2O@C 59N . Chem Sci 2018; 9:5666-5671. [PMID: 30062000 PMCID: PMC6050629 DOI: 10.1039/c8sc01031e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/02/2018] [Indexed: 12/21/2022] Open
Abstract
We report a high-resolution photoelectron imaging study of cryogenically-cooled H2O@C60- and H2O@C59N- endohedral fullerene anions. The electron affinity (EA) of H2O@C60 is measured to be 2.6923 ± 0.0008 eV, which is 0.0088 eV higher than the EA of C60, while the EA of H2O@C59N is measured to be 3.0058 eV ± 0.0007 eV, which is 0.0092 eV lower than the EA of C59N. The opposite shifts are found to be due to the different electrostatic interactions between the encapsulated water molecule and the fullerene cages in the two systems. There is a net coulombic attraction between the guest and host in H2O@C60-, but a repulsive interaction in H2O@C59N-. We have also observed low-frequency features in the photoelectron spectra tentatively attributed to the hindered rotational excitations of the encapsulated H2O molecule, providing further insights into the guest-host interactions in H2O@C60- and H2O@C59N-.
Collapse
Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , USA .
| | - Yuan Liu
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , USA .
| | - Yoshifumi Hashikawa
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Qian-Fan Zhang
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , USA .
| | - Yasujiro Murata
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Lai-Sheng Wang
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , USA .
| |
Collapse
|
28
|
Miao X, Zhu J, Zhao K, Zhan H, Yue W. Determining the Humidity-Dependent Ortho-to- Para Ratio of Water Vapor at Room Temperature Using Terahertz Spectroscopy. APPLIED SPECTROSCOPY 2018; 72:1040-1046. [PMID: 29714077 DOI: 10.1177/0003702818772853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The origin of the water spin isomers observed under various physico-chemical conditions is of great interest, including that of H2O molecules in the gas phase. Here, terahertz time-domain spectroscopy (THz-TDS) was used to study the humidity-dependent ortho-to- para (O/P) ratio of water vapor at room temperature. The relative contents of para and ortho molecules were obtained by fitting the absorption lines of water vapor showing the relationship between the spin isomer contents and humidity. Larger O/P ratios with values of ∼3.2 were observed at lower humidity (<20%) due to the stronger attractive forces of para molecules. The concentration of the ortho isomers then began to decrease at higher humidity (>20%) due to the preferential formation of dimers and clusters at increasing concentrations. Thus, the ratio gradually decreased with increasing humidity.
Collapse
Affiliation(s)
- Xinyang Miao
- 1 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
- 2 Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing, China
| | - Jing Zhu
- 2 Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing, China
| | - Kun Zhao
- 1 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
- 2 Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing, China
| | - Honglei Zhan
- 2 Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing, China
| | - Wenzheng Yue
- 1 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
| |
Collapse
|
29
|
Meier B, Kouřil K, Bengs C, Kouřilová H, Barker TC, Elliott SJ, Alom S, Whitby RJ, Levitt MH. Spin-Isomer Conversion of Water at Room Temperature and Quantum-Rotor-Induced Nuclear Polarization in the Water-Endofullerene H_{2}O@C_{60}. PHYSICAL REVIEW LETTERS 2018; 120:266001. [PMID: 30004780 DOI: 10.1103/physrevlett.120.266001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/24/2018] [Indexed: 05/15/2023]
Abstract
Water exists in two forms, para and ortho, that have nuclear spin states with different symmetries. Here we report the conversion of fullerene-encapsulated para water to ortho water. The enrichment of para water at low temperatures is monitored via changes in the electrical polarizability of the material. Upon rapid dissolution of the material in toluene the excess para water converts to ortho water. In H_{2}^{16}O@C_{60} the conversion leads to a slow increase in the NMR signal. In H_{2}^{17}O@C_{60} the conversion gives rise to weak signal enhancements attributed to quantum-rotor-induced nuclear spin polarization. The time constants for the para-to-ortho conversion of fullerene-encapsulated water in ambient temperature solution are estimated as 30±4 s for the ^{16}O isotopolog of water, and 16±3 s for the ^{17}O isotopolog.
Collapse
Affiliation(s)
- Benno Meier
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Karel Kouřil
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Christian Bengs
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Hana Kouřilová
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Timothy C Barker
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Stuart J Elliott
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Shamim Alom
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Richard J Whitby
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| |
Collapse
|
30
|
Prisk TR, Hoffmann C, Kolesnikov AI, Mamontov E, Podlesnyak AA, Wang X, Kent PRC, Anovitz LM. Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures. PHYSICAL REVIEW LETTERS 2018; 120:196001. [PMID: 29799243 DOI: 10.1103/physrevlett.120.196001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Indexed: 05/15/2023]
Abstract
Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factor reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10-100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.
Collapse
Affiliation(s)
- T R Prisk
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 208996-6100, USA
| | - C Hoffmann
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A A Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - X Wang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - P R C Kent
- Center for Nanophase Materials Sciences and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L M Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
31
|
Bloodworth S, Gräsvik J, Alom S, Kouřil K, Elliott SJ, Wells NJ, Horsewill AJ, Mamone S, Jiménez-Ruiz M, Rols S, Nagel U, Rõõm T, Levitt MH, Whitby RJ. Synthesis and Properties of Open Fullerenes Encapsulating Ammonia and Methane. Chemphyschem 2018; 19:266-276. [PMID: 29131544 PMCID: PMC5838534 DOI: 10.1002/cphc.201701212] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Indexed: 12/03/2022]
Abstract
We describe the synthesis and characterisation of open fullerene (1) and its reduced form (2) in which CH4 and NH3 are encapsulated, respectively. The 1H NMR resonance of endohedral NH3 is broadened by scalar coupling to the quadrupolar 14n nucleus, which relaxes rapidly. This broadening is absent for small satellite peaks, which are attributed to natural abundance 15N. The influence of the scalar relaxation mechanism on the linewidth of the 1H ammonia resonance is probed by variable temperature NMR. A rotational correlation time of τc=1.5 ps. is determined for endohedral NH3, and of τc=57±5 ps. for the open fullerene, indicating free rotation of the encapsulated molecule. IR spectroscopy of NH3@2 at 5 K identifies three vibrations of NH3 (ν1, ν3 and ν4) redshifted in comparison with free NH3, and temperature dependence of the IR peak intensity indicates the presence of a large number of excited translational/ rotational states. Variable temperature 1H NMR spectra indicate that endohedral CH4 is also able to rotate freely at 223 K, on the NMR timescale. Inelastic neutron scattering (INS) spectra of CH4@1 show both rotational and translational modes of CH4. Energy of the first excited rotational state (J=1) of CH4@1 is significantly lower than that of free CH4.
Collapse
Affiliation(s)
| | - John Gräsvik
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Shamim Alom
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Karel Kouřil
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | | | - Neil J Wells
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Anthony J Horsewill
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Salvatore Mamone
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Stéphane Rols
- Institut Laue-Langevin, CS 20156, 38042, Grenoble, France
| | - Urmas Nagel
- National Institute of Chemical Physics and Biophysics, Akadeemia Tee 23, Tallinn, 12618, Estonia
| | - Toomas Rõõm
- National Institute of Chemical Physics and Biophysics, Akadeemia Tee 23, Tallinn, 12618, Estonia
| | | | | |
Collapse
|
32
|
Kouřil K, Meier B, Alom S, Whitby RJ, Levitt MH. Alignment of 17O-enriched water-endofullerene H 2O@C 60 in a liquid crystal matrix. Faraday Discuss 2018; 212:517-532. [PMID: 30238100 DOI: 10.1039/c8fd00095f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We present a 17O and 1H NMR study of molecular endofullerene H2O@C60 dissolved in the nematic liquid crystal N-(4-methoxybenzylidene)-4-butylaniline (MBBA). The 17O NMR peak is split into five components by the 17O residual quadrupolar coupling, each of which is split into a triplet by the 1H-17O residual dipolar coupling and scalar coupling. The splittings are analysed in terms of the partial alignment of the encapsulated water molecules. Order parameters describing the alignment are estimated. It is found that the preferential orientation of the endohedral water molecule has the molecular plane perpendicular to the liquid crystal director.
Collapse
Affiliation(s)
- Karel Kouřil
- University of Southampton, School of Chemistry, SO171BJ, Southampton, UK.
| | - Benno Meier
- University of Southampton, School of Chemistry, SO171BJ, Southampton, UK.
| | - Shamim Alom
- University of Southampton, School of Chemistry, SO171BJ, Southampton, UK.
| | - Richard J Whitby
- University of Southampton, School of Chemistry, SO171BJ, Southampton, UK.
| | - Malcolm H Levitt
- University of Southampton, School of Chemistry, SO171BJ, Southampton, UK.
| |
Collapse
|
33
|
Kalugina YN, Roy PN. Potential energy and dipole moment surfaces for HF@C60: Prediction of spectral and electric response properties. J Chem Phys 2017; 147:244303. [DOI: 10.1063/1.5006589] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yulia N. Kalugina
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| |
Collapse
|
34
|
Felker PM, Bačić Z. Accurate quantum calculations of translation-rotation eigenstates in electric-dipole-coupled H2O@C60 assemblies. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.02.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
35
|
Felker PM, Bačić Z. Electric-dipole-coupled H2O@C60 dimer: Translation-rotation eigenstates from twelve-dimensional quantum calculations. J Chem Phys 2017; 146:084303. [DOI: 10.1063/1.4976526] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Peter M. Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062, China
| |
Collapse
|
36
|
Kouřil K, Wickens C, Meier B, Alom S, Gräsvik J, Whitby RJ, Levitt MH. NMR of molecular endofullerenes dissolved in a nematic liquid crystal. Phys Chem Chem Phys 2017; 19:11793-11801. [DOI: 10.1039/c7cp00906b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We report the NMR of the molecular endofullerenes H2@C60, H2O@C60 and HF@C60 dissolved in the nematic liquid crystal N-(4-methoxybenzylidene)-4-butylaniline (MBBA).
Collapse
Affiliation(s)
- Karel Kouřil
- School of Chemistry
- University of Southampton
- SO17 1BJ Southampton
- UK
| | | | - Benno Meier
- School of Chemistry
- University of Southampton
- SO17 1BJ Southampton
- UK
| | - Shamim Alom
- School of Chemistry
- University of Southampton
- SO17 1BJ Southampton
- UK
| | - John Gräsvik
- School of Chemistry
- University of Southampton
- SO17 1BJ Southampton
- UK
| | | | | |
Collapse
|
37
|
Felker PM, Vlček V, Hietanen I, FitzGerald S, Neuhauser D, Bačić Z. Explaining the symmetry breaking observed in the endofullerenes H2@C60, HF@C60, and H2O@C60. Phys Chem Chem Phys 2017; 19:31274-31283. [DOI: 10.1039/c7cp06062a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Symmetry breaking has been recently observed in the endofullerenes M@C60 (M = H2, HF, H2O), manifesting in the splittings of the three-fold degenerate ground states of the endohedral ortho-H2, ortho-H2O and the j = 1 level of HF.
Collapse
Affiliation(s)
- Peter M. Felker
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
| | - Vojtěch Vlček
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
| | - Isaac Hietanen
- Department of Physics and Astronomy
- Oberlin College
- Oberlin
- USA
| | | | - Daniel Neuhauser
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
| | - Zlatko Bačić
- Department of Chemistry
- New York University
- New York
- USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai
| |
Collapse
|
38
|
Carrillo-Bohórquez O, Valdés Á, Prosmiti R. Temperature Dependence of HeBr 2 Isomers' Stability through Rovibrational Multiconfiguration Time-Dependent Hartree Calculations. J Phys Chem A 2016; 120:9458-9464. [PMID: 27802030 DOI: 10.1021/acs.jpca.6b09107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The multiconfiguration time-dependent Hartree (MCTDH) method using a six-dimensional Hamiltonian that includes all rotational and vibrational degrees of freedom and an ab initio potential energy surface was employed to calculate the rovibronic states of the HeBr2 van der Waals complex. All rotational states of energies within 7 cm -1 with respect to the energy of the linear ground state were calculated without restriction of the total angular momentum. In total, we obtained 500 and 320 rotationally excited states of the ground vibrational T-shaped and linear isomers of the HeBr2, respectively, and compared them with those predicted by the rigid rotor model. A thermodynamic model was then introduced to determine the relative stability of the two conformers as a function of the temperature. On the basis of the present results, the linear conformers were found to be energetically more stable than the T-shaped ones by 1.14 cm-1 at T = 0 K, whereas conversion from linear to T-shaped complexes was observed at temperatures above 2.87 K.
Collapse
Affiliation(s)
- Orlando Carrillo-Bohórquez
- Departamento de Física, Universidad Nacional de Colombia , Calle 26, Cra 39, Edificio 404, Bogotá, Colombia
| | - Álvaro Valdés
- Departamento de Física, Universidad Nacional de Colombia , Calle 26, Cra 39, Edificio 404, Bogotá, Colombia
| | - Rita Prosmiti
- Institute of Fundamental Physics (IFF-CSIC), CSIC , Serrano 123, 28006 Madrid, Spain
| |
Collapse
|
39
|
Suzuki H, Ishida M, Yamashita M, Otani C, Kawachi K, Kasama Y, Kwon E. Rotational dynamics of Li + ions encapsulated in C 60 cages at low temperatures. Phys Chem Chem Phys 2016; 18:31384-31387. [PMID: 27841436 DOI: 10.1039/c6cp06949e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Li+ ions encapsulated in fullerene C60 cages (Li+@C60) are expected to be suitable as molecular switches that respond to local electric fields. In this study, the rotational dynamics of Li+ ions in C60 cages at low temperatures are experimentally revealed for the first time using terahertz absorption spectroscopy. In crystalline [Li+@C60](PF6-), the Li+ ion rotates in the carbon cage even at 150 K. The rotational mode gradually changes into a librational mode below 120 K, which is associated with the localization of Li+ ions due to the electrostatic interactions with its screening image charge on the C60 cage as well as with the neighboring Li+@C60 and PF6- ions. A simple rotational/librational energy scheme for the Li+ ions successfully explains the spectroscopic results, and the potential of Li+@C60 as a molecular switch is discussed based on the energy scheme.
Collapse
Affiliation(s)
- Hal Suzuki
- Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - Misaki Ishida
- Terahertz Sensing and Imaging Research Team, Center for Advanced Photonics, RIKEN, Sendai, Miyagi 980-0845, Japan
| | - Masatsugu Yamashita
- Terahertz Sensing and Imaging Research Team, Center for Advanced Photonics, RIKEN, Sendai, Miyagi 980-0845, Japan
| | - Chiko Otani
- Terahertz Sensing and Imaging Research Team, Center for Advanced Photonics, RIKEN, Sendai, Miyagi 980-0845, Japan
| | | | | | - Eunsang Kwon
- Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| |
Collapse
|
40
|
Krachmalnicoff A, Bounds R, Mamone S, Alom S, Concistrè M, Meier B, Kouřil K, Light ME, Johnson MR, Rols S, Horsewill AJ, Shugai A, Nagel U, Rõõm T, Carravetta M, Levitt MH, Whitby RJ. The dipolar endofullerene HF@C60. Nat Chem 2016; 8:953-7. [DOI: 10.1038/nchem.2563] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 05/25/2016] [Indexed: 12/22/2022]
|
41
|
Felker PM, Bačić Z. Communication: Quantum six-dimensional calculations of the coupled translation-rotation eigenstates of H2O@C60. J Chem Phys 2016; 144:201101. [DOI: 10.1063/1.4953180] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Peter M. Felker
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062, China
| |
Collapse
|
42
|
Kolesnikov AI, Reiter GF, Choudhury N, Prisk TR, Mamontov E, Podlesnyak A, Ehlers G, Seel AG, Wesolowski DJ, Anovitz LM. Quantum Tunneling of Water in Beryl: A New State of the Water Molecule. PHYSICAL REVIEW LETTERS 2016; 116:167802. [PMID: 27152824 DOI: 10.1103/physrevlett.116.167802] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 05/15/2023]
Abstract
Using neutron scattering and ab initio simulations, we document the discovery of a new "quantum tunneling state" of the water molecule confined in 5 Å channels in the mineral beryl, characterized by extended proton and electron delocalization. We observed a number of peaks in the inelastic neutron scattering spectra that were uniquely assigned to water quantum tunneling. In addition, the water proton momentum distribution was measured with deep inelastic neutron scattering, which directly revealed coherent delocalization of the protons in the ground state.
Collapse
Affiliation(s)
- Alexander I Kolesnikov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - George F Reiter
- Physics Department, University of Houston, Houston, Texas 77204, USA
| | - Narayani Choudhury
- Math and Science Division, Lake Washington Institute of Technology, Kirkland, Washington 98034, USA; School of Science, Technology, Engineering and Math, University of Washington, Bothell, Washington 98011, USA
| | - Timothy R Prisk
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrey Podlesnyak
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - George Ehlers
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrew G Seel
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - David J Wesolowski
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Lawrence M Anovitz
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
43
|
Mamone S, Johnson MR, Ollivier J, Rols S, Levitt MH, Horsewill AJ. Symmetry-breaking in the H2@C60 endofullerene revealed by inelastic neutron scattering at low temperature. Phys Chem Chem Phys 2016; 18:1998-2005. [DOI: 10.1039/c5cp07146a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fine structure of the rotational ground state of molecular ortho-hydrogen confined inside the fullerene cage C60 is investigated by inelastic neutron scattering (INS).
Collapse
Affiliation(s)
- Salvatore Mamone
- School of Physics and Astronomy
- University of Nottingham
- NG7 2RD Nottingham
- UK
| | | | | | | | | | | |
Collapse
|
44
|
Xu M, Ye S, Bačić Z. General Selection Rule in the Inelastic Neutron Scattering Spectroscopy of a Diatomic Molecule Confined Inside a Near-Spherical Nanocavity. J Phys Chem Lett 2015; 6:3721-3725. [PMID: 26722746 DOI: 10.1021/acs.jpclett.5b01505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Knowledge of the relevant selection rules is crucial for the accurate interpretation of experimental spectra in general. There has been a consensus for a long time that the incoherent inelastic neutron scattering (INS) spectroscopy of the vibrations of discrete molecular compunds is free from any selection rules. We contradict this widely held view by presenting an analytical derivation of the general selection rule for the INS spectroscopy of a hydrogen molecule inside a near-spherical nanocavity. It defines all forbidden transitions, originating in a range of initial translation-rotation (TR) states, ground and excited, of the caged para- and ortho-H2, as well as HD, that are unobservable in the INS spectra. These predictions are amenable to experimental verification. In addition, we demonstrate that the general selection rule applies to the INS spectroscopy of any diatomic molecule in a nanocavity with near-spherical symmetry, which exhibits strong TR coupling. Its existence strongly suggests that similar selection rules apply to the INS spectra of other molecular and supramolecular systems, and need to be identified.
Collapse
Affiliation(s)
- Minzhong Xu
- Department of Chemistry, New York University , New York, New York 10003, United States
| | - Shufeng Ye
- Department of Chemistry, New York University , New York, New York 10003, United States
| | - Zlatko Bačić
- Department of Chemistry, New York University , New York, New York 10003, United States
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, 200062, China
| |
Collapse
|
45
|
Meier B, Mamone S, Concistrè M, Alonso-Valdesueiro J, Krachmalnicoff A, Whitby RJ, Levitt MH. Electrical detection of ortho-para conversion in fullerene-encapsulated water. Nat Commun 2015; 6:8112. [PMID: 26299447 PMCID: PMC4560827 DOI: 10.1038/ncomms9112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/20/2015] [Indexed: 01/01/2023] Open
Abstract
Water exists in two spin isomers, ortho and para, that have different nuclear spin states. In bulk water, rapid proton exchange and hindered molecular rotation obscure the direct observation of two spin isomers. The supramolecular endofullerene H2O@C60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show that the bulk dielectric constant of this substance depends on the ortho/para ratio, and changes slowly in time after a sudden temperature jump, due to nuclear spin conversion. The attribution of the effect to ortho-para conversion is validated by comparison with nuclear magnetic resonance and quantum theory. The change in dielectric constant is consistent with an electric dipole moment of 0.51±0.05 Debye for an encapsulated water molecule, indicating the partial shielding of the water dipole by the encapsulating cage. The dependence of bulk dielectric constant on nuclear spin isomer composition appears to be a previously unreported physical phenomenon.
Collapse
Affiliation(s)
- Benno Meier
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Salvatore Mamone
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Maria Concistrè
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | | | | | - Richard J. Whitby
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Malcolm H. Levitt
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| |
Collapse
|