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Devi S, Prasad V. Dynamics of coupled rotors in external fields. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 302:122983. [PMID: 37393672 DOI: 10.1016/j.saa.2023.122983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 05/19/2023] [Accepted: 06/03/2023] [Indexed: 07/04/2023]
Abstract
Coupled hindered rotor model is crucial for exploring the rotational dynamics of complex molecules under different external environments. When coupled hindered rotor molecules are subjected to the combined action of static electric and laser fields, their rotational dynamics get significantly modified, leading to interesting physics. In this study, we solve the time-independent Schrödinger equation for the coupled pair of rotors in the combined action of static electric and laser fields using the nine-point finite difference method and obtain rotational energy spectra and eigenvectors. We then use the partition function approach to understand thermal behaviour by studying thermal properties like heat capacity and entropy. We also explore the impact of temperature, coupling strength, and external fields strength parameters on these properties. The orientation of the coupled rotor is strongly dependent on the coupling strength between the coupled rotors as well as the hindrance. We analyse this directional parameter under a broad range of barrier height, coupling strength, and external fields strength parameters. Our analysis may provide insight into the rich and interesting physics, which may pave the way for future experimental and theoretical studies in this area.
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Affiliation(s)
- Sumana Devi
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India; Department of Physics, Miranda House, University of Delhi, Delhi 110007, India.
| | - Vinod Prasad
- Department of Physics, Swami Shradhanand College, University of Delhi, Delhi 110036, India.
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Zarcone SR, Chu GM, Ehnbom A, Cardenal A, Fiedler T, Bhuvanesh N, Hall MB, Gladysz JA. Toward Frameworks with Multiple Aligned and Interactive Fe(CO) 3 Rotators: Syntheses and Structures of Diiron Complexes Linked by Two trans-Diaxial α,ω-Diphosphine Ligands Ar 2P(CH 2) nPAr 2. Inorg Chem 2021; 60:3314-3330. [PMID: 33571407 DOI: 10.1021/acs.inorgchem.0c03737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions of (η4-benzylideneacetone)Fe(CO)3 and the α,ω-diphosphines Ar2P(CH2)nPAr2 afford the trigonal bipyramidal diiron tetraphosphorus complexes trans,trans-(CO)3Fe[Ar2P(CH2)nPAr2]2Fe(CO)3 (n/Ar = 3/Ph 3, 4/Ph 4a, 4/p-tol 4b; 56-19%). Crystal structures establish essentially parallel P-Fe-P axes, iron-iron distances of 5.894(9)-5.782(1) Å (3) and 6.403(1)-6.466(1) Å (4a,b), and van der Waals radii of 4.45 Å for the Fe(CO)3 rotators, the planes of which are offset by 0.029-1.665 Å. Analogous reactions of Ph2P(CH2)6PPh2 yield the square pyramidal monoiron complex trans-(CO)3Fe[Ph2P(CH2)6PPh2] (6', 31%), a rare case where a diphosphine spans trans basal positions (∠P-Fe-P 147.4(2)°). Both 3 and 6' exhibit two CO 13C NMR signals at room temperature, indicating slow exchange on the NMR time scale, which in the former could entail Fe(CO)3/Fe(CO)3 gearing. Under analogous conditions, 4a,b exhibit one signal. Previously reported adducts of Fe(CO)3 and Ph2P(CH2)nPPh2 are surveyed (1:1, n = 1-5; 2:2, n = 5), and the IR νC≡O band patterns and energies of all complexes analyzed with the aid of DFT calculations. The diiron complexes are preferred thermodynamically. Attention is given to limiting types of Fe(CO)3/Fe(CO)3 interactions in the diiron complexes.
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Affiliation(s)
- Samuel R Zarcone
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Gong M Chu
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Andreas Ehnbom
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Ashley Cardenal
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Tobias Fiedler
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Michael B Hall
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
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Magann A, Chen L, Ho TS, Rabitz H. Quantum optimal control of multiple weakly interacting molecular rotors in the time-dependent Hartree approximation. J Chem Phys 2019; 150:164303. [PMID: 31042879 DOI: 10.1063/1.5091520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We perform quantum optimal control simulations, based on the Time-Dependent Hartree (TDH) approximation, for systems of three to five dipole-dipole coupled OCS rotors. A control electric field is used to steer all of the individual rotors, arranged in chains and regular polygons in a plane, toward either identical or unique objectives. The goal is to explore the utility of the TDH approximation to model the field-induced dynamics of multiple interacting rotors in the weak dipole-dipole coupling regime. A stochastic hill climbing approach is employed to seek an optimal control field that achieves the desired objectives at a specified target time. We first show that multiple rotors in chain and polygon geometries can be identically oriented in the same direction; these cases do not significantly depend on the presence of the dipole-dipole interaction. Additionally, in particular geometrical arrangements, we demonstrate that individual rotors can be uniquely manipulated toward different objectives with the same field. Specifically, it is shown that for a three rotor chain, the two end rotors can be identically oriented in a specific direction while keeping the middle rotor in its ground state, and for an equilateral triangle, two rotors can be identically oriented in a specific direction while the third rotor is oriented in the opposite direction. These multirotor unique objective cases exploit the shape of the field in coordination with dipole-dipole coupling between the rotors. Comparisons to numerically exact calculations, utilizing the TDH-determined fields, are given for all optimal control studies involving systems of three rotors.
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Affiliation(s)
- Alicia Magann
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Linhan Chen
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Tak-San Ho
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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Zhang ZY, Wei D, Hu Z, Liu JM. EPR steering of polar molecules in pendular states and their dynamics under intrinsic decoherence. RSC Adv 2018; 8:35928-35935. [PMID: 35558491 PMCID: PMC9088734 DOI: 10.1039/c8ra06342g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/11/2018] [Indexed: 02/03/2023] Open
Abstract
The EPR steering of two coupled polar molecules in pendular states is investigated and their dynamics under intrinsic decoherence are analyzed.
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Affiliation(s)
- Zuo-Yuan Zhang
- State Key Laboratory of Precision Spectroscopy
- East China Normal University
- Shanghai
- China
| | - Daxiu Wei
- Department of Physics and Shanghai Key Laboratory of Magnetic Resonance
- East China Normal University
- Shanghai
- China
| | - Zhengfeng Hu
- Key Laboratory of Quantum Optics
- Shanghai Institute of Optics and Fine Mechanics
- Chinese Academy of Science
- Shanghai
- China
| | - Jin-Ming Liu
- State Key Laboratory of Precision Spectroscopy
- East China Normal University
- Shanghai
- China
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Quantum Correlations and Coherence of Polar Symmetric Top Molecules in Pendular States. Sci Rep 2017; 7:17822. [PMID: 29259261 PMCID: PMC5736622 DOI: 10.1038/s41598-017-18148-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 12/06/2017] [Indexed: 11/12/2022] Open
Abstract
We consider two ultracold polar symmetric top molecules coupled by dipole-dipole interaction in an external electric field with appreciable intensity gradient, serving as the physical carrier of quantum information. Each molecule is induced to undergo pendular oscillations under the strong static electric field. Based on the pendular states of polar symmetric top molecules as candidate qubits, we investigate the bipartite quantum correlations of the two polar molecular system for the thermal equilibrium states, characterized by negativity and quantum discord, and then analyze the corresponding coherence, measured by relative entropy and l1 norm. Furthermore, we also examine the dynamics of the entanglement and coherence of the system in the presence of intrinsic decoherence, and explore the relations of their temporal evolution with various physical system parameters for two different initial Bell states. It is found that quantum correlations and coherence of the two polar molecules in pendular states can be manipulated by adjusting appropriate reduced variables including external electric field, dipole-dipole interaction, ambient temperature and decoherence factor. Our findings could be used for molecular quantum computing based on rotational states.
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