Quantum-classical path integral: A rigorous approach to condensed phase dynamics

2015 ◽  
Vol 115 (18) ◽  
pp. 1209-1214 ◽  
Author(s):  
Nancy Makri
Keyword(s):  
Path Integral ◽  
Condensed Phase ◽  
Phase Dynamics ◽  
Rigorous Approach ◽  
Classical Path

Blip-summed quantum–classical path integral with cumulative quantum memory

2016 ◽  
Vol 195 ◽  
pp. 81-92 ◽  
Author(s):  
Nancy Makri
Keyword(s):  
Path Integral ◽  
Degrees Of Freedom ◽  
Quantum Memory ◽  
Integral Methods ◽  
Acceleration Techniques ◽  
Classical Path ◽  
Forced Oscillator ◽  
Influence Functional ◽  
Harmonic Bath ◽  
Explicit Enumeration

The quantum-classical path integral (QCPI) offers a rigorous methodology for simulating quantum mechanical processes in condensed-phase environments treated in full atomistic detail. This paper describes the implementation of QCPI on system–bath models, which are frequently employed in studying the dynamics of reactive processes. The QCPI methodology incorporates all effects associated with stimulated phonon absorption and emission as its crudest limit, thus can (in some regimes) converge faster than influence functional-based path integral methods specifically designed for system–bath Hamiltonians. It is shown that the QCPI phase arising from a harmonic bath can be summed analytically with respect to the discrete bath degrees of freedom and expressed in terms of precomputed influence functional coefficients, avoiding the explicit enumeration of forced oscillator trajectories, whose number grows exponentially with the length of quantum memory. Further, adoption of the blip decomposition (which classifies the system paths based on the time length over which their forward and backward components are not identical) and a cumulative treatment of the QCPI phase between blips allows elimination of the majority of system paths, leading to a dramatic increase in efficiency. The generalization of these acceleration techniques to anharmonic environments is discussed.

Iterative quantum-classical path integral with dynamically consistent state hopping

2016 ◽  
Vol 144 (4) ◽  
pp. 044108 ◽  
Author(s):  
Peter L. Walters ◽  
Nancy Makri
Keyword(s):  
Path Integral ◽  
Classical Path

scholarly journals Condensed Phase Laser Induced Harpoon Reactions

1988 ◽  
Vol 9 (1-3) ◽  
pp. 1-26 ◽  
Author(s):  
Mario E. Fajardo ◽  
R. Withnall ◽  
J. Feld ◽  
F. Okada ◽  
W. Lawrence ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Condensed Phase ◽  
Rare Gas ◽  
Many Body ◽  
Phase Dynamics ◽  
Two Photon ◽  
Radiation Fields ◽  
Electron Transitions ◽  
Charge Transfer Reactions

Laser induced charge transfer reactions of halogens in rare gas solids and liquids provide a powerful means for the study of condensed phase dynamics. Many-body effects with respect to both electronic and nuclear coordinates, and cooperative interactions with radiation fields, are some of the studied phenomena that are highlighted in this article.The pertinence of these ionic reactions to chemistry in solids is demonstrated in photodissociation studies of molecular halogens in rare gas matrices. The coexistence of both delocalized and localized charge transfer states in solid xenon doped with atomic halogens is presented and dynamical consequences—charge separation, self-trapping and energy storage—are discussed. Static and dynamic solvent effects in liquid phase harpoon reactions are considered. The characterization of cooperative excitations— two-photon, two-electron transitions—in liquid solutions is presented.

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