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Stachowiak M, Grabowska E, Wang XG, Carrington T, Szalewicz K, Jankowski P. Theory cracks old data: Rovibrational energy levels of orthoH 2-CO derived from experiment. SCIENCE ADVANCES 2024; 10:eadj8632. [PMID: 38394212 PMCID: PMC10889352 DOI: 10.1126/sciadv.adj8632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Measurements of rovibrational spectra of clusters provide physical insight only if spectral lines can be assigned to pairs of quantum states, and further insight is obtained if one can deduce the quantitative energy-level pattern. Both steps can be so difficult that some measured spectra remain unassigned, one example is orthoH2-CO. To extend the scope of spectroscopic insights, we propose to use theoretical information in interpretation of spectra. We first performed high accuracy, full-dimensional calculations of the orthoH2-CO spectrum, at the highest practically achievable levels of electronic structure theory and quantum nuclear dynamics. Then, an iterative, theory-guided method developed here allowed us to fully interpret the spectrum of orthoH2-CO, extending the range of van der Waals clusters for which spectroscopy can provide physical insights.
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Affiliation(s)
- Marcin Stachowiak
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Ewelina Grabowska
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Xiao-Gang Wang
- Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Tucker Carrington
- Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Krzysztof Szalewicz
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
| | - Piotr Jankowski
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
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2
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Li Y, Zhai Y, Li H. MLRNet: Combining the Physics-Motivated Potential Models with Neural Networks for Intermolecular Potential Energy Surface Construction. J Chem Theory Comput 2023; 19:1421-1431. [PMID: 36826225 DOI: 10.1021/acs.jctc.2c01049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
A physics-based machine learning model called MLRNet has been developed to construct the high-accuracy two-body intermolecular potential energy surface (IPES). The outputs of the neural network are integrated into the physically realistic Morse/long-range (MLR) function, which ensures that the MLRNet has meaningful extrapolation at both short and long ranges and solves the asymptotic problem in common neural network potential (NNP) models. The neural network representation of the MLR parameters is more flexible and more efficient than the polynomial expansion in the conventional mdMLR model, especially for systems containing nonrigid monomer(s). The present work illustrates the basic framework of the current MLRNet model, including (i) how to combine the physically meaningful MLR function with different possible NN structures, (ii) the preservation of permutation symmetry, and (iii) the predetermination of the long-range function uLR. We choose two realistic systems to demonstrate the performance of MLRNet: the three-dimensional IPES of CO2-He including the CO2 antisymmetric vibration Q3 and the six-dimensional IPES of the H2O-Ar system. In both cases, the fitting errors of the MLRNet are several times smaller than those of the conventional mdMLR model. Both short-range and long-range extrapolation tests were performed to illustrate the extrapolation ability of the MLRNet and its damping function version. Moreover, for the 6-D H2O-Ar system, the MLRNet only needs 1596 trainable parameters, which is almost equal to the number needed for the 5-D mdMLR model (1509) and half that needed for the PIP-NN model (3501) within similar accuracy, which illustrates the model efficiency in high-dimensional IPES fitting.
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Affiliation(s)
- You Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Yu Zhai
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Hui Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
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3
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DuránCaballero L, Schran C, Brieuc F, Marx D. Neural network interaction potentials for para-hydrogen with flexible molecules. J Chem Phys 2022; 157:074302. [DOI: 10.1063/5.0100953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The study of molecular impurities in para-hydrogen ( pH2) clusters is key to push forward our understanding of intra- and intermolecular interactions, including their impact on the superfluid response of this bosonic quantum solvent. This includes tagging with only one or very few pH2, the microsolvation regime for intermediate particle numbers, and matrix isolation with many solvent molecules. However, the fundamental coupling between the bosonic pH2 environment and the (ro-)vibrational motion of molecular impurities remains poorly understood. Quantum simulations can, in principle, provide the necessary atomistic insight, but they require very accurate descriptions of the involved interactions. Here, we present a data-driven approach for the generation of impurity⋯ pH2 interaction potentials based on machine learning techniques, which retain the full flexibility of the dopant species. We employ the well-established adiabatic hindered rotor (AHR) averaging technique to include the impact of the nuclear spin statistics on the symmetry-allowed rotational quantum numbers of pH2. Embedding this averaging procedure within the high-dimensional neural network potential (NNP) framework enables the generation of highly accurate AHR-averaged NNPs at coupled cluster accuracy, namely, explicitly correlated coupled cluster single, double, and scaled perturbative triples, CCSD(T*)-F12a/aVTZcp, in an automated manner. We apply this methodology to the water and protonated water molecules as representative cases for quasi-rigid and highly flexible molecules, respectively, and obtain AHR-averaged NNPs that reliably describe the corresponding H2O⋯ pH2 and H3O+⋯ pH2 interactions. Using path integral simulations, we show for the hydronium cation, H3O+, that umbrella-like tunneling inversion has a strong impact on the first and second pH2 microsolvation shells. The automated and data-driven nature of our protocol opens the door to the study of bosonic pH2 quantum solvation for a wide range of embedded impurities.
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Affiliation(s)
- Laura DuránCaballero
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christoph Schran
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Fabien Brieuc
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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4
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Otani H, Nakahara H, Goto H, Kuma S, Momose T. Electronic spectroscopy of Mg-phthalocyanine embedded in cold hydrogen clusters produced by a pulsed nozzle. J Chem Phys 2021; 155:044309. [PMID: 34340371 DOI: 10.1063/5.0056499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cold clusters of molecular hydrogen were created using a pulsed nozzle. The thermodynamical states of the clusters were characterized by measuring the cluster beam velocity and the laser-induced fluorescence (LIF) spectra of embedded molecules. Two distinct velocity components were identified in the beam that originates from different clustering mechanisms. The fast velocity component corresponds to the expansion of H2 from the gas phase, while the slow velocity component corresponds to the expansion from the liquid phase. The velocity distribution of these two components showed no significant difference between the expansions of para and normal hydrogen. In this study, LIF spectroscopy of single Mg-phthalocyanine molecules embedded in the H2 clusters consisting of 105 H2 molecules was used to investigate the properties of the fast component. The observed peak frequencies of the LIF signals, compared to those observed in helium droplets, were used to infer the possible presence of the liquid phase in the fast component of the H2 clusters below 5 K. The shift, linewidth, and splitting in the spectra, which strongly depend on the ortho/para ratio, are attributed to the local configurations of hydrogen in the vicinity of the probe molecules.
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Affiliation(s)
- Hatsuki Otani
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Hiroko Nakahara
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Haruka Goto
- Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Susumu Kuma
- Atomic, Molecular, and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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Uhl F, Marx D. Quantum Microsolvation of Protonated Methane with ^{4}He: Large-Amplitude Motion Heavily Influences Bosonic Exchange. PHYSICAL REVIEW LETTERS 2019; 123:123002. [PMID: 31633943 DOI: 10.1103/physrevlett.123.123002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 01/28/2019] [Indexed: 06/10/2023]
Abstract
Quantum simulations of small CH_{5}^{+}·^{4}He_{n} complexes disclose significant and antagonistic impact of small-amplitude local vibrational motion vs large-amplitude global fluxional motion within the CH_{5}^{+} impurity on helium in real and permutation space. While the former significantly enhances bosonic exchange in the surrounding ^{4}He microsolvation shell compared to the rigid-body reference, the latter greatly suppresses long permutation cycles, which is traced back to the different nature of these quantum fluctuations. Therefore, it is expected that the resulting impact on local superfluidity is generic for fluctuating impurities in bosonic environments.
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Affiliation(s)
- Felix Uhl
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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6
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Li H, Zhang XL, Zeng T, Le Roy RJ, Roy PN. Suppression of Parahydrogen Superfluidity in a Doped Nanoscale Bose Fluid Mixture. PHYSICAL REVIEW LETTERS 2019; 123:093001. [PMID: 31524438 DOI: 10.1103/physrevlett.123.093001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/07/2019] [Indexed: 06/10/2023]
Abstract
Helium (^{4}He) nanodroplets provide a unique environment to observe the microscopic origins of superfluidity. The search for another superfluid substance has been an ongoing quest in the field of quantum fluids. Nearly two decades ago, experiments on doped parahydrogen (p-H_{2}) clusters embedded in ^{4}He droplets displayed anomalous spectroscopic signatures that were interpreted as a sign of the superfluidity of p-H_{2} [S. Grebenev et al., Science 289, 1532 (2000)SCIEAS0036-807510.1126/science.289.5484.1532]. Here, we observe, using first-principles quantum Monte Carlo simulations, a phase separation between a symmetric and localized p-H_{2} core and ^{4}He shells. The p-H_{2} core has minimal superfluid response. These findings are consistent with the recorded spectra but not with their original interpretation, and lead us to conclude that doped p-H_{2} clusters form a nonsuperfluid core in ^{4}He droplets.
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Affiliation(s)
- Hui Li
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, China
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Xiao-Long Zhang
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, China
| | - Tao Zeng
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Robert J Le Roy
- 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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7
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Uhl F, Marx D. Helium Tagging of Protonated Methane in Messenger Spectroscopy: Does It Interfere with the Fluxionality of CH5
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? Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Felix Uhl
- Lehrstuhl für Theoretische Chemie; Ruhr-Universität Bochum; 44780 Bochum Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie; Ruhr-Universität Bochum; 44780 Bochum Germany
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8
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Uhl F, Marx D. Helium Tagging of Protonated Methane in Messenger Spectroscopy: Does It Interfere with the Fluxionality of CH5
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? Angew Chem Int Ed Engl 2018; 57:14792-14795. [DOI: 10.1002/anie.201808531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Felix Uhl
- Lehrstuhl für Theoretische Chemie; Ruhr-Universität Bochum; 44780 Bochum Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie; Ruhr-Universität Bochum; 44780 Bochum Germany
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9
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Liu JM, Zhang XL, Zhai Y, Li H. Theoretical Study of Infrared Spectra of OCS-( pH 2) 2, OCS-( oD 2) 2, OCS-(HD) 2, and Mixed OCS- pH 2-He Trimers. J Phys Chem A 2018; 122:2915-2926. [DOI: 10.1021/acs.jpca.7b12708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jing-Min Liu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Xiao-Long Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Yu Zhai
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Hui Li
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
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10
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Hou D, Zhang XL, Zhai Y, Li H. The Role of High Excitations in Constructing Sub-spectroscopic Accuracy Intermolecular Potential of He-HCN: Critically Examined by the High-Resolution Spectra with Resonance States. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1712231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Dan Hou
- Institute of Functional Materials and Agricultural Applied Chemistry, College of Science, Jiangxi Agricultural University, Nanchang 330045, China
| | - Xiao-Long Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
| | - Yu Zhai
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
| | - Hui Li
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
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11
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Liu JM, Zhai Y, Li H. Explicit correlation treatment of the six-dimensional potential energy surface and predicted infrared spectra for OCS–H2. J Chem Phys 2017; 147:044313. [DOI: 10.1063/1.4996086] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jing-Min Liu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
| | - Yu Zhai
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
| | - Hui Li
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
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12
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Raston PL, Jäger W. Rotational Spectroscopic Study of Quantum Solvation in Isotopologic ( pH 2) N–CO Clusters. J Phys Chem A 2017; 121:3671-3678. [DOI: 10.1021/acs.jpca.7b02192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul L. Raston
- Department
of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
| | - Wolfgang Jäger
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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13
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Surin L, Schnell M. Rotational spectrum of the NH 3–He van der Waals complex. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201713203045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Farrelly D, Iñarrea M, Lanchares V, Salas JP. Lieb-Liniger-like model of quantum solvation in CO-(4)HeN clusters. J Chem Phys 2016; 144:204301. [PMID: 27250300 DOI: 10.1063/1.4949537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Small (4)He clusters doped with various molecules allow for the study of "quantum solvation" as a function of cluster size. A peculiarity of quantum solvation is that, as the number of (4)He atoms is increased from N = 1, the solvent appears to decouple from the molecule which, in turn, appears to undergo free rotation. This is generally taken to signify the onset of "microscopic superfluidity." Currently, little is known about the quantum mechanics of the decoupling mechanism, mainly because the system is a quantum (N + 1)-body problem in three dimensions which makes computations difficult. Here, a one-dimensional model is studied in which the (4)He atoms are confined to revolve on a ring and encircle a rotating CO molecule. The Lanczos algorithm is used to investigate the eigenvalue spectrum as the number of (4)He atoms is varied. Substantial solvent decoupling is observed for as few as N = 5 (4)He atoms. Examination of the Hamiltonian matrix, which has an almost block diagonal structure, reveals increasingly weak inter-block (solvent-molecule) coupling as the number of (4)He atoms is increased. In the absence of a dopant molecule the system is similar to a Lieb-Liniger (LL) gas and we find a relatively rapid transition to the LL limit as N is increased. In essence, the molecule initially-for very small N-provides a central, if relatively weak, attraction to organize the cluster; as more (4)He atoms are added, the repulsive interactions between the identical bosons start to dominate as the solvation ring (shell) becomes more crowded which causes the molecule to start to decouple. For low N, the molecule pins the atoms in place relative to itself; as N increases the atom-atom repulsion starts to dominate the Hamiltonian and the molecule decouples. We conclude that, while the notion of superfluidity is a useful and correct description of the decoupling process, a molecular viewpoint provides complementary insights into the quantum mechanism of the transition from a molecular cluster to a quantum solvated molecule.
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Affiliation(s)
- D Farrelly
- Departamento de Matemáticas y Computación, Universidad de La Rioja, 26006 Logroño, Spain
| | - M Iñarrea
- Área de Física Aplicada, Universidad de La Rioja, 26006 Logroño, Spain
| | - V Lanchares
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
| | - J P Salas
- Área de Física Aplicada, Universidad de La Rioja, 26006 Logroño, Spain
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16
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Hou D, Ma YT, Zhang XL, Li H. The origins of intra- and inter-molecular vibrational couplings: A case study of H2O-Ar on full and reduced-dimensional potential energy surface. J Chem Phys 2016; 144:014301. [DOI: 10.1063/1.4939089] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dan Hou
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
| | - Yong-Tao Ma
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
| | - Xiao-Long Zhang
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
| | - Hui Li
- Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People’s Republic of China
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17
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Schmidt M, Fernández JM, Faruk N, Nooijen M, Le Roy RJ, Morilla JH, Tejeda G, Montero S, Roy PN. Raman Vibrational Shifts of Small Clusters of Hydrogen Isotopologues. J Phys Chem A 2015; 119:12551-61. [DOI: 10.1021/acs.jpca.5b08852] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthew Schmidt
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - José M. Fernández
- Laboratory
of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, E-28006 Madrid, Spain
| | - Nabil Faruk
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Marcel Nooijen
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Robert J. Le Roy
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Juan H. Morilla
- Laboratory
of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, E-28006 Madrid, Spain
| | - Guzmán Tejeda
- Laboratory
of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, E-28006 Madrid, Spain
| | - Salvador Montero
- Laboratory
of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, E-28006 Madrid, Spain
| | - Pierre-Nicholas Roy
- Department
of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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18
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Raston PL, Jäger W. Microwave spectroscopy of the seeded binary and ternary clusters CO-(pH2)2, CO-pH2-He, CO-HD, and CO-(oD2)(N=1,2). J Chem Phys 2015; 142:144308. [PMID: 25877579 DOI: 10.1063/1.4917420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report the Fourier transform microwave spectra of the a-type J = 1-0 transitions of the binary and ternary CO-(pH2)2, CO-pH2-He, CO-HD, and CO-(oD2)N=1,2 clusters. In addition to the normal isotopologue of CO for all clusters, we observed the transitions of the minor isotopologues, (13)C(16)O, (12)C(18)O, and (13)C(18)O, for CO-(pH2)2 and CO-pH2-He. All transitions lie within 335 MHz of the experimentally or theoretically predicted values. In comparison to previously reported infrared spectra [Moroni et al., J. Chem. Phys. 122, 094314 (2005)], we are able to tentatively determine the vibrational shift for CO-pH2-He, in addition to its b-type J = 1-0 transition frequency. The a-type frequency of CO-pH2-He is similar to that of CO-He2 [Surin et al., Phys. Rev. Lett. 101, 233401 (2008)], suggesting that the pH2 molecule has a strong localizing effect on the He density. Perturbation theory analysis of CO-oD2 reveals that it is approximately T-shaped, with an anisotropy of the intermolecular potential amounting to ∼9 cm(-1).
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Affiliation(s)
- Paul L Raston
- Department of Chemistry, University of Adelaide, SA 5005, Australia
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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Dvorak M, Müller M, Bünermann O, Stienkemeier F. Size dependent transition to solid hydrogen and argon clusters probed via spectroscopy of PTCDA embedded in helium nanodroplets. J Chem Phys 2015; 140:144301. [PMID: 24735293 DOI: 10.1063/1.4870395] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Complexes made of either Ar(N) or (H2)N clusters (N = 1-170) and a single PTCDA molecule (3,4,9,10-perylene-tetracarboxylic-dianhydride) are assembled inside helium droplets and spectroscopically studied via laser-induced fluorescence spectroscopy. The frequency shift and line-broadening are analyzed as a function of N and of the pick-up order of the PTCDA and cluster material in order to track liquid or solid properties of the clusters. For argon, the solid phase is observed for N > 10 above which the pick-up order dramatically influences the localization of the chromophore with respect to the Ar cluster. If the droplets are doped first with Ar, the chromophore remains on the surface of a solid cluster whereas for the reversed pick-up order the molecule is surrounded by an argon shell. At N < 10 wetting and the formation of the first solvation shell are observed. For para-hydrogen, a transition to the solid is observed at N ~ 20-25, confirming previous theoretical predictions on the existence of a liquid-like phase at such small sizes, even below the bulk hydrogen freezing temperature.
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Affiliation(s)
- Matthieu Dvorak
- Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Markus Müller
- Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Oliver Bünermann
- Institut für Physikalische Chemie, Georg-August-Universität Tammannstr. 6, 37077 Göttingen, Germany
| | - Frank Stienkemeier
- Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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20
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Zhang XL, Li H, Le Roy RJ, Roy PN. Microwave and infrared spectra of CO–(pH2)2, CO–(oD2)2, and mixed CO–pH2–He trimers. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1568-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Berg M, Accardi A, Paulus B, Schmidt B. Rotationally adiabatic pair interactions of para- and ortho-hydrogen with the halogen molecules F2, Cl2, and Br2. J Chem Phys 2014; 141:074303. [PMID: 25149782 DOI: 10.1063/1.4892599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The present work is concerned with the weak interactions between hydrogen and halogen molecules, i.e., the interactions of pairs H2-X2 with X = F, Cl, Br, which are dominated by dispersion and quadrupole-quadrupole forces. The global minimum of the four-dimensional (4D) coupled cluster with singles and doubles and perturbative triples (CCSD(T)) pair potentials is always a T shaped structure where H2 acts as the hat of the T, with well depths (De) of 1.3, 2.4, and 3.1 kJ/mol for F2, Cl2, and Br2, respectively. MP2/AVQZ results, in reasonable agreement with CCSD(T) results extrapolated to the basis set limit, are used for detailed scans of the potentials. Due to the large difference in the rotational constants of the monomers, in the adiabatic approximation, one can solve the rotational Schrödinger equation for H2 in the potential of the X2 molecule. This yields effective two-dimensional rotationally adiabatic potential energy surfaces where pH2 and oH2 are point-like particles. These potentials for the H2-X2 complexes have global and local minima for effective linear and T-shaped complexes, respectively, which are separated by 0.4-1.0 kJ/mol, where oH2 binds stronger than pH2 to X2, due to higher alignment to minima structures of the 4D-pair potential. Further, we provide fits of an analytical function to the rotationally adiabatic potentials.
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Affiliation(s)
- Matthias Berg
- Institut für Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Antonio Accardi
- Institut für Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Beate Paulus
- Institut für Chemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Burkhard Schmidt
- Institut für Mathematik, Freie Universität Berlin, Arnimallee 6, D-14195 Berlin, Germany
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Faruk N, Schmidt M, Li H, Le Roy RJ, Roy PN. First-principles prediction of the Raman shifts in parahydrogen clusters. J Chem Phys 2014; 141:014310. [DOI: 10.1063/1.4885275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Nabil Faruk
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Matthew Schmidt
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Hui Li
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People's Republic of China
| | - Robert J. Le Roy
- 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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Herdman CM, Inglis S, Roy PN, Melko RG, Del Maestro A. Path-integral Monte Carlo method for Rényi entanglement entropies. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:013308. [PMID: 25122411 DOI: 10.1103/physreve.90.013308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Indexed: 06/03/2023]
Abstract
We introduce a quantum Monte Carlo algorithm to measure the Rényi entanglement entropies in systems of interacting bosons in the continuum. This approach is based on a path-integral ground state method that can be applied to interacting itinerant bosons in any spatial dimension with direct relevance to experimental systems of quantum fluids. We demonstrate how it may be used to compute spatial mode entanglement, particle partitioned entanglement, and the entanglement of particles, providing insights into quantum correlations generated by fluctuations, indistinguishability, and interactions. We present proof-of-principle calculations and benchmark against an exactly soluble model of interacting bosons in one spatial dimension. As this algorithm retains the fundamental polynomial scaling of quantum Monte Carlo when applied to sign-problem-free models, future applications should allow for the study of entanglement entropy in large-scale many-body systems of interacting bosons.
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Affiliation(s)
- C M Herdman
- Department of Physics, University of Vermont, Burlington, Vermont 05405, USA
| | - Stephen Inglis
- Department of Physics, Arnold Sommerfeld Center for Theoretical Physics, and Center for Nanoscience, Ludwig-Maximilians-Universität München, Theresienstraße 37, 80333 Munich, Germany and Department of Physics and Astronomy, University of Waterloo, Ontario, Canada N2L 3G1
| | - P-N Roy
- Department of Chemistry, University of Waterloo, Ontario, Canada N2L 3G1
| | - R G Melko
- Department of Physics and Astronomy, University of Waterloo, Ontario, Canada N2L 3G1 and Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada N2L 2Y5
| | - A Del Maestro
- Department of Physics, University of Vermont, Burlington, Vermont 05405, USA and Vermont Complex Systems Center, University of Vermont, Burlington, Vermont 05405, USA
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24
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Yan Y, Blume D. Abnormal superfluid fraction of harmonically trapped few-fermion systems. PHYSICAL REVIEW LETTERS 2014; 112:235301. [PMID: 24972215 DOI: 10.1103/physrevlett.112.235301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 06/03/2023]
Abstract
Superfluidity is a fascinating phenomenon that, at the macroscopic scale, leads to dissipationless flow and the emergence of vortices. While these macroscopic manifestations of superfluidity are well described by theories that have their origin in Landau's two-fluid model, our microscopic understanding of superfluidity is far from complete. Using analytical and numerical ab initio approaches, this Letter determines the superfluid fraction and local superfluid density of small harmonically trapped two-component Fermi gases as a function of the interaction strength and temperature. At low temperature, we find that the superfluid fraction is, in certain regions of the parameter space, negative. This counterintuitive finding is traced back to the symmetry of the system's ground state wave function, which gives rise to a diverging quantum moment of inertia I(q). Analogous abnormal behavior of I(q) has been observed in even-odd nuclei at low temperature. Our predictions can be tested in modern cold atom experiments.
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Affiliation(s)
- Yangqian Yan
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
| | - D Blume
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
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Wairegi A, Gamboa A, Burbanks AD, Lee EA, Farrelly D. Microscopic superfluidity in 4He clusters stirred by a rotating impurity molecule. PHYSICAL REVIEW LETTERS 2014; 112:143401. [PMID: 24765958 DOI: 10.1103/physrevlett.112.143401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Indexed: 06/03/2023]
Abstract
The effective moment of inertia of a CO impurity molecule in 4HeN and p-(H2)N solvent clusters initially increases with N but then commences a nonclassical decrease at N=4 (4He) or N=6 (p-H2). This suggests molecule-solvent decoupling and a transition to microscopic superfluidity. However, the quantum decoupling mechanism has not been elucidated. To understand the decoupling mechanism, a one-dimensional model is introduced in which the 4He atoms are confined to a ring. This model captures the physics and shows that decoupling happens primarily because of bosonic solvent-solvent repulsion. Quantum Monte Carlo and basis set calculations suggest that the system can be modeled as a stirred Tonks-Girardeau gas. This allows the N-particle time-dependent Schrödinger equation to be solved directly. Computations of the integrated particle current reveal a threshold for stirring and current generation, indicative of superfluidity.
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Affiliation(s)
- Angeline Wairegi
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
| | - Antonio Gamboa
- Institut de Sciences Moléculaires d'Orsay, CNRS UMR 8214, Université de Paris-Sud 11, Bâtiment 210, F91405, Orsay Cedex, France
| | - Andrew D Burbanks
- Department of Mathematics, University of Portsmouth, Portsmouth, P01 3HF, United Kingdom
| | - Ernestine A Lee
- FivePrime Therapeutics, Two Corporate Drive, South San Francisco, California 94080, USA
| | - David Farrelly
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
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Zeng T, Roy PN. Microscopic molecular superfluid response: theory and simulations. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:046601. [PMID: 24647079 DOI: 10.1088/0034-4885/77/4/046601] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Since its discovery in 1938, superfluidity has been the subject of much investigation because it provides a unique example of a macroscopic manifestation of quantum mechanics. About 60 years later, scientists successfully observed this phenomenon in the microscopic world though the spectroscopic Andronikashvili experiment in helium nano-droplets. This reduction of scale suggests that not only helium but also para-H2 (pH2) can be a candidate for superfluidity. This expectation is based on the fact that the smaller number of neighbours and surface effects of a finite-size cluster may hinder solidification and promote a liquid-like phase. The first prediction of superfluidity in pH2 clusters was reported in 1991 based on quantum Monte Carlo simulations. The possible superfluidity of pH2 was later indirectly observed in a spectroscopic Andronikashvili experiment in 2000. Since then, a growing number of studies have appeared, and theoretical simulations have been playing a special role because they help guide and interpret experiments. In this review, we go over the theoretical studies of pH2 superfluid clusters since the experiment of 2000. We provide a historical perspective and introduce the basic theoretical formalism along with key experimental advances. We then present illustrative results of the theoretical studies and comment on the possible future developments in the field. We include sufficient theoretical details such that the review can serve as a guide for newcomers to the field.
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Affiliation(s)
- Tao Zeng
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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27
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Li H, Zhang XL, Le Roy RJ, Roy PN. Analytic Morse/long-range potential energy surfaces and predicted infrared spectra for CO–H2 dimer and frequency shifts of CO in (para-H2)N N = 1–20 clusters. J Chem Phys 2013; 139:164315. [DOI: 10.1063/1.4826595] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fajardo ME. High-Resolution Rovibrational Spectroscopy of Carbon Monoxide Isotopologues Isolated in Solid Parahydrogen. J Phys Chem A 2013; 117:13504-12. [DOI: 10.1021/jp407267u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mario E. Fajardo
- Air Force Research Laboratory, Munitions
Directorate, Ordnance Division, Energetic Materials Branch, AFRL/RWME, 2306 Perimeter
Road, Eglin Air Force Base, Florida 32542-5910, United States
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29
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Zeng T, Guillon G, Cantin JT, Roy PN. Probing the Superfluid Response of para-Hydrogen with a Sulfur Dioxide Dopant. J Phys Chem Lett 2013; 4:2391-2396. [PMID: 26704292 DOI: 10.1021/jz401188j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We recently presented the first attempt at using an asymmetric top molecule (para-water) to probe the superfluidity of nanoclusters (of para-hydrogen) [ Zeng , T. ; Li , H. ; Roy , P.-N. J. Phys. Chem. Lett. 2013 , 4 , 18 - 22 ]. Unfortunately, para-water could not be used to probe the para-hydrogen superfluid response. We now report a theoretical simulation of sulfur dioxide rotating in para-hydrogen clusters and show that this asymmetric top can serve as a genuine probe of superfluidity. With this probe, we predict that as few as four para-hydrogen molecules are enough to form a superfluid cluster, the smallest superfluid system to date. We also propose the concept of "exchange superfluid fraction" as a more precise measurement. New superfluid scenarios brought about by an asymmetric top dopant and potential experimental measurements are discussed.
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Affiliation(s)
- Tao Zeng
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Grégoire Guillon
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Joshua T Cantin
- 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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Hayashi M, Ohshima Y. Sub-Doppler Electronic Spectra of Benzene–(H2)n Complexes. J Phys Chem A 2013; 117:9819-30. [DOI: 10.1021/jp312754v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masato Hayashi
- Institute
for Molecular Science, National Institutes of Natural Sciences, Myodaiji,
Okazaki 444-8585, Japan
| | - Yasuhiro Ohshima
- Institute
for Molecular Science, National Institutes of Natural Sciences, Myodaiji,
Okazaki 444-8585, Japan
- SOKENDAI, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
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31
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Guillon G, Zeng T, Roy PN. On the origin and convergence of a post-quantization constrained propagator for path integral simulations of rigid bodies. J Chem Phys 2013; 138:184101. [DOI: 10.1063/1.4803118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Zeng T, Li H, Roy PN. Simulating Asymmetric Top Impurities in Superfluid Clusters: A para-Water Dopant in para-Hydrogen. J Phys Chem Lett 2013; 4:18-22. [PMID: 26291205 DOI: 10.1021/jz3017705] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the first simulation study of bosonic clusters doped with an asymmetric top molecule. The path-integral Monte Carlo method with the latest methodological advance in treating rigid-body rotation [Noya, E. G.; Vega, C.; McBride, C. J. Chem. Phys.2011, 134, 054117] is employed to study a para-water impurity in para-hydrogen clusters with up to 20 para-hydrogen molecules. The growth pattern of the doped clusters is similar in nature to that of pure clusters. The para-water molecule appears to rotate freely in the cluster. The presence of para-water substantially quenches the superfluid response of para-hydrogen with respect to the space-fixed frame.
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Affiliation(s)
- Tao Zeng
- †Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Hui Li
- ‡Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People's Republic of China
| | - Pierre-Nicholas Roy
- †Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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33
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Li H, Ma YT. An intramolecular vibrationally excited intermolecular potential for He–OCS: Globally tested by simulation of vibrational shifts for OCS in HeN N = 1 − 100 Clusters. J Chem Phys 2012; 137:234310. [PMID: 23267489 DOI: 10.1063/1.4772186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Hui Li
- Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, People's Republic of China.
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34
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Dempster SP, Sukhorukov O, Lei QY, Jäger W. Rotational spectroscopic study of hydrogen cyanide embedded in small 4He clusters. J Chem Phys 2012; 137:174303. [DOI: 10.1063/1.4762862] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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