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Morcillo-Arencibia MF, Alcaraz-Pelegrina JM, Sarsa AJ, Randazzo JM. An off-center endohedrally confined hydrogen molecule. Phys Chem Chem Phys 2022; 24:22971-22977. [PMID: 36125249 DOI: 10.1039/d2cp03456e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we address the problem of a C60 endohedrally confined hydrogen molecule through a configuration-interaction approach to electronic dynamics. Modeling the confinement by means of a combination of two Woods-Saxon potentials, we analyze the stability of the system as a function of the nuclei position through the behavior of the electronic spectrum. After studying the convergence of two different partial wave expansions, one related to the molecular Coulomb centers and the other related to the off-centering of the C60 well, we found that the second approach provides a more accurate description of the system. Furthermore, we observed that the inter-atomic distance changes based on the position of the atoms inside the cavity. Thus, to obtain the most favourable energetic configuration for the molecule, it should be positioned inside the cavity next to the structure, where its size decreases.
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Affiliation(s)
- Milagros F Morcillo-Arencibia
- Departamento de Física, Campus de Rabanales, Edif. C2. Universidad de Córdoba, E-14071 Córdoba, Spain. .,Centro Atómico Bariloche, CNEA and CONICET, S. C. de Bariloche, Río Negro, Argentina
| | | | - Antonio J Sarsa
- Departamento de Física, Campus de Rabanales, Edif. C2. Universidad de Córdoba, E-14071 Córdoba, Spain.
| | - Juan M Randazzo
- Centro Atómico Bariloche, CNEA and CONICET, S. C. de Bariloche, Río Negro, Argentina
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2
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Saroj A, Venkatnarayan R, Mishra BK, Panda AN, Narayanasami S. Improved Estimates of Host‐Guest Interaction Energies for Endohedral Fullerenes Containing Rare Gas Atoms, Small Molecules, and Cations. Chemphyschem 2022; 23:e202200413. [DOI: 10.1002/cphc.202200413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/18/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Arti Saroj
- IIT BHU: Indian Institute of Technology BHU Varanasi Chemistry 221005 Varanasi INDIA
| | | | | | - Aditya N. Panda
- IIT Guwahati: Indian Institute of Technology Guwahati Chemistry 781039 INDIA
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3
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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.
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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.
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4
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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.
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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
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5
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Hauser AW, Pototschnig JV. Vibronic Coupling in Spherically Encapsulated, Diatomic Molecules: Prediction of a Renner-Teller-like Effect for Endofullerenes. J Phys Chem A 2022; 126:1674-1680. [PMID: 35258966 PMCID: PMC8935370 DOI: 10.1021/acs.jpca.1c10970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
In the year 1933,
Herzberg and Teller realized that the potential
energy surface of a triatomic, linear molecule splits into two as
soon as the molecule is bent. The phenomenon, later dubbed the Renner–Teller
effect due to the detailed follow-up work of Renner on the subject,
describes the coupling of a symmetry-reducing molecular vibration
with degenerate electronic states. In this article, we show that a
very similar type of nonadiabatic coupling can occur for certain translational
degrees of freedom of diatomic, electronically degenerate molecules
when trapped in a nearly spherical or cylindrical quantum confinement,
e.g., realized through electromagnetic fields or molecular encapsulation.
We illustrate this on the example of fullerene-encapsulated nitric
oxide, and provide a prediction of its interesting, perturbed vibronic
spectrum.
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Affiliation(s)
- Andreas W Hauser
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Johann V Pototschnig
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
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6
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Bacanu GR, Jafari T, Aouane M, Rantaharju J, Walkey M, Hoffman G, Shugai A, Nagel U, Jiménez-Ruiz M, Horsewill AJ, Rols S, Rõõm T, Whitby RJ, Levitt MH. Experimental determination of the interaction potential between a helium atom and the interior surface of a C 60 fullerene molecule. J Chem Phys 2021; 155:144302. [PMID: 34654304 DOI: 10.1063/5.0066817] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interactions between atoms and molecules may be described by a potential energy function of the nuclear coordinates. Nonbonded interactions between neutral atoms or molecules are dominated by repulsive forces at a short range and attractive dispersion forces at a medium range. Experimental data on the detailed interaction potentials for nonbonded interatomic and intermolecular forces are scarce. Here, we use terahertz spectroscopy and inelastic neutron scattering to determine the potential energy function for the nonbonded interaction between single He atoms and encapsulating C60 fullerene cages in the helium endofullerenes 3He@C60 and 4He@C60, synthesized by molecular surgery techniques. The experimentally derived potential is compared to estimates from quantum chemistry calculations and from sums of empirical two-body potentials.
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Affiliation(s)
- George Razvan Bacanu
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Tanzeeha Jafari
- National Institute of Chemical Physics and Biophysics, Tallinn 12618, Estonia
| | | | - Jyrki Rantaharju
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Mark Walkey
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Gabriela Hoffman
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Anna Shugai
- National Institute of Chemical Physics and Biophysics, Tallinn 12618, Estonia
| | - Urmas Nagel
- National Institute of Chemical Physics and Biophysics, Tallinn 12618, Estonia
| | | | - Anthony J Horsewill
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Stéphane Rols
- Institut Laue-Langevin, BP 156, 38042 Grenoble, France
| | - Toomas Rõõm
- National Institute of Chemical Physics and Biophysics, Tallinn 12618, Estonia
| | - 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
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7
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Abstract
Hydrogen molecules exist in the form of two distinct isomers that can be interconverted by physical catalysis. These ortho and para forms have different thermodynamical properties. Over the last century, the catalysts developed to convert hydrogen from one form to another, in laboratories and industries, were magnetic and the interpretations relied on magnetic dipolar interactions. The variety concentration of a sample and the conversion rates induced by a catalytic action were mostly measured by thermal methods related to the diffusion of the o-p reaction heat. At the turning of the new century, the nature of the studied catalysts and the type of measures and motivations completely changed. Catalysts investigated now are non-magnetic and new spectroscopic measurements have been developed. After a fast survey of the past studies, the review details the spectroscopic methods, emphasizing their originalities, performances and refinements: how Infra-Red measurements characterize the catalytic sites and follow the conversion in real-time, Ultra-Violet irradiations explore the electronic nature of the reaction and hyper-frequencies driving the nuclear spins. The new catalysts, metallic or insulating, are detailed to display the operating electronic structure. New electromagnetic mechanisms, involving energy and momenta transfers, are discovered providing a classification frame for the newly observed reactions.
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8
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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
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9
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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
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10
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Singh MK, Shukla P, Khatua M, Rajaraman G. A Design Criteria to Achieve Giant Ising-Type Anisotropy in Co II -Encapsulated Metallofullerenes. Chemistry 2019; 26:464-477. [PMID: 31506987 DOI: 10.1002/chem.201903618] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/05/2019] [Indexed: 11/10/2022]
Abstract
Discovery of permanent magnetisation in molecules just like in hard magnets decades ago led to the proposal of utilising these molecules for information storage devices and also as Q-bits in quantum computing. A significant breakthrough with a blocking temperature as high as 80 K has been recently reported for lanthanocene complexes. While enhancing the blocking temperature further remains one of the primary challenges, obtaining molecules that are suitable for the fabrication of the devices sets the bar very high in this area. Encouraged by the fact that our earlier predictions of potential single-molecule magnets (SMMs) in lanthanide-containing endohedral fullerenes have been verified, here we set out to undertake a comprehensive study on CoII -ion-encapsulated fullerene as potential SMMs. To study this class of molecules, we have utilised an array of theoretical methods ranging from density functional to ab initio CASSCF/NEVPT2 methods for obtaining reliable estimate of zero-field splitting parameters D and E. Additionally, we have also employed, for the first time a combination of molecular dynamics based on DFT methods coupled with CASSCF/NEVPT2 methods to seek the role of conformational isomers in the relaxation of magnetisation. Particularly, we have studied, Co@C28 , Co@C38 and Co@C48 cages and their isomers as potential target molecules that could yield substantial magnetic anisotropy. Our calculations categorically reveal a very large Ising anisotropy in this class of molecules, with Co@C48 cages predicted to yield D values as high as -127 cm-1 . Our calculations on the smaller cages reveal the free movement of CoII ion inside the cage, leading to the likely scenario of faster relaxation of magnetisation. However, larger fullerene cages were found to solve this issue. Further models with incorporating units such as {CoOZn}, {CoScZnN} inside larger fullerenes yield axial zero-field splitting values as high as -200 cm-1 with negligible E/D values. As these units represent a strong axiality coupled with a viable way to obtain air-stable low-coordinate CoII complexes, this opens up a new paradigm in the search of SMMs in this class of molecules.
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Affiliation(s)
- Mukesh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Pratima Shukla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Munmun Khatua
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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11
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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.
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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
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12
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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.
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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.
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13
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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.
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Affiliation(s)
- Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003, USA
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14
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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.
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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
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15
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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.
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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.
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16
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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
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17
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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
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18
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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).
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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
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19
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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.
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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
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20
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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.
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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
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21
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Mamone S, Jiménez-Ruiz M, Johnson MR, Rols S, Horsewill AJ. Experimental, theoretical and computational investigation of the inelastic neutron scattering spectrum of a homonuclear diatomic molecule in a nearly spherical trap: H2@C60. Phys Chem Chem Phys 2016; 18:29369-29380. [DOI: 10.1039/c6cp06059e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we report a methodology for calculating the inelastic neutron scattering spectrum of homonuclear diatomic molecules confined within nano-cavities of spherical symmetry.
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Affiliation(s)
- Salvatore Mamone
- School of Physics and Astronomy
- University of Nottingham
- NG7 2RD Nottingham
- UK
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