Non-adiabatic dynamics around a conical intersection with surface-hopping coupled coherent states

Journal Article · Tue Jun 21 00:00:00 EDT 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4954189· OSTI ID:22660742

Humeniuk, Alexander; Mitrić, Roland ^[1]

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1. Institut für Physikalische und Theoretische Chemie, Julius-Maximilians Universität Würzburg, Emil-Fischer-Straße 42, 97074 Würzburg (Germany)

A surface-hopping extension of the coupled coherent states-method [D. Shalashilin and M. Child, Chem. Phys. 304, 103-120 (2004)] for simulating non-adiabatic dynamics with quantum effects of the nuclei is put forward. The time-dependent Schrödinger equation for the motion of the nuclei is solved in a moving basis set. The basis set is guided by classical trajectories, which can hop stochastically between different electronic potential energy surfaces. The non-adiabatic transitions are modelled by a modified version of Tully’s fewest switches algorithm. The trajectories consist of Gaussians in the phase space of the nuclei (coherent states) combined with amplitudes for an electronic wave function. The time-dependent matrix elements between different coherent states determine the amplitude of each trajectory in the total multistate wave function; the diagonal matrix elements determine the hopping probabilities and gradients. In this way, both interference effects and non-adiabatic transitions can be described in a very compact fashion, leading to the exact solution if convergence with respect to the number of trajectories is achieved and the potential energy surfaces are known globally. The method is tested on a 2D model for a conical intersection [A. Ferretti, J. Chem. Phys. 104, 5517 (1996)], where a nuclear wavepacket encircles the point of degeneracy between two potential energy surfaces and interferes with itself. These interference effects are absent in classical trajectory-based molecular dynamics but can be fully incorpo rated if trajectories are replaced by surface hopping coupled coherent states.

• OSTI ID: 22660742
• Journal Information: Journal of Chemical Physics, Vol. 144, Issue 23; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANNIHILATION OPERATORS
EIGENSTATES
ELECTRIC POTENTIAL
INTERFERENCE
MATRIX ELEMENTS
MOLECULAR DYNAMICS METHOD
NUCLEI
PHASE SPACE
POTENTIAL ENERGY
SCHROEDINGER EQUATION
SURFACES
TIME DEPENDENCE
WAVE FUNCTIONS