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Full-Text Articles in Chemistry
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott Reid, Phalgun Lolur, Richard Dawes
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott Reid, Phalgun Lolur, Richard Dawes
Chemistry Faculty Research and Publications
We report a global analysis of spin-orbit coupling in the mono-halocarbenes, CH(D)X, where X = Cl, Br, and I. These are model systems for examining carbene singlet-triplet energy gaps and spin-orbit coupling. Over the past decade, rich data sets collected using single vibronic level emission spectroscopy and stimulated emission pumping spectroscopy have yielded much information on the ground vibrational level structure and clearly demonstrated the presence of perturbations involving the low-lying triplet state. To model these interactions globally, we compare two approaches. First, we employ a diabatic treatment of the spin-orbit coupling, where the coupling matrix elements are written in …
Rotational Quenching Of H2O By He: Mixed Quantum/Classical Theory And Comparison With Quantum Results, Mikhail V. Ivanov, Marie-Lise Dubernet, Dmitri Babikov
Rotational Quenching Of H2O By He: Mixed Quantum/Classical Theory And Comparison With Quantum Results, Mikhail V. Ivanov, Marie-Lise Dubernet, Dmitri Babikov
Chemistry Faculty Research and Publications
The mixed quantum/classical theory (MQCT) formulated in the space-fixed reference frame is used to compute quenching cross sections of several rotationally excited states of water molecule by impact of He atom in a broad range of collision energies, and is tested against the full-quantum calculations on the same potential energy surface. In current implementation of MQCT method, there are two major sources of errors: one affects results at energies below 10 cm−1, while the other shows up at energies above 500 cm−1. Namely, when the collision energy E is below the state-to-state transition energy ΔE the …
Mixed Quantum/Classical Theory For Inelastic Scattering Of Asymmetric-Top-Rotor + Atom In The Body-Fixed Reference Frame And Application To The H2O + He System, Alexander Semenov, Marie-Lise Dubernet, Dmitri Babikov
Mixed Quantum/Classical Theory For Inelastic Scattering Of Asymmetric-Top-Rotor + Atom In The Body-Fixed Reference Frame And Application To The H2O + He System, Alexander Semenov, Marie-Lise Dubernet, Dmitri Babikov
Chemistry Faculty Research and Publications
The mixed quantum/classical theory (MQCT) for inelastic molecule-atom scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys.139, 174108 (2013)] is extended to treat a general case of an asymmetric-top-rotor molecule in the body-fixed reference frame. This complements a similar theory formulated in the space-fixed reference-frame [M. Ivanov, M.-L. Dubernet, and D. Babikov, J. Chem. Phys.140, 134301 (2014)]. Here, the goal was to develop an approximate computationally affordable treatment of the rotationally inelastic scattering and apply it to H2O + He. We found that MQCT is somewhat less accurate at lower scattering energies. For example, below E …
Mixed Quantum/Classical Theory Of Rotationally And Vibrationally Inelastic Scattering In Space-Fixed And Body-Fixed Reference Frames, Alexander Semenov, Dmitri Babikov
Mixed Quantum/Classical Theory Of Rotationally And Vibrationally Inelastic Scattering In Space-Fixed And Body-Fixed Reference Frames, Alexander Semenov, Dmitri Babikov
Chemistry Faculty Research and Publications
We formulated the mixed quantum/classical theory for rotationally and vibrationally inelastic scattering process in the diatomic molecule + atom system. Two versions of theory are presented, first in the space-fixed and second in the body-fixed reference frame. First version is easy to derive and the resultant equations of motion are transparent, but the state-to-state transition matrix is complex-valued and dense. Such calculations may be computationally demanding for heavier molecules and/or higher temperatures, when the number of accessible channels becomes large. In contrast, the second version of theory requires some tedious derivations and the final equations of motion are rather complicated …
Equivalence Of The Ehrenfest Theorem And The Fluid-Rotor Model For Mixed Quantum/Classical Theory Of Collisional Energy Transfer, Alexander Semenov, Dmitri Babikov
Equivalence Of The Ehrenfest Theorem And The Fluid-Rotor Model For Mixed Quantum/Classical Theory Of Collisional Energy Transfer, Alexander Semenov, Dmitri Babikov
Chemistry Faculty Research and Publications
The theory of two seemingly different quantum/classical approaches to collisional energy transfer and ro-vibrational energy flow is reviewed: a heuristic fluid-rotor method, introduced earlier to treat recombination reactions[M. Ivanov and D. Babikov, J. Chem. Phys.134, 144107 (Year: 2011)10.1063/1.3576103], and a more rigorous method based on the Ehrenfest theorem. It is shown analytically that for the case of a diatomic molecule + quencher these two methods are entirely equivalent. Notably, they both make use of the average moment of inertia computed as inverse of average of inverse of the distributed moment of inertia. Despite this equivalence, each of the two formulations …