Spin-mapping approach for nonadiabatic molecular dynamics
| Autor: | Jeremy O. Richardson, Johan E. Runeson |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Chemical Physics (physics.chem-ph)
Physics 010304 chemical physics Computational complexity theory FOS: Physical sciences General Physics and Astronomy Semiclassical physics 010402 general chemistry 01 natural sciences 0104 chemical sciences Molecular dynamics symbols.namesake Classical mechanics Physics - Chemical Physics Phase space 0103 physical sciences symbols Coherent states Physical and Theoretical Chemistry Hamiltonian (quantum mechanics) Quantum Harmonic oscillator |
| Zdroj: | The Journal of Chemical Physics. 151:044119 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.5100506 |
| Popis: | We propose a trajectory-based method for simulating nonadiabatic dynamics in molecular systems with two coupled electronic states. Employing a quantum-mechanically exact mapping of the two-level problem to a spin-1/2 coherent state, we construct a classical phase space of a spin vector constrained to a spherical surface with a radius consistent with the quantum magnitude of the spin. In contrast with the singly-excited harmonic oscillator basis used in Meyer-Miller-Stock-Thoss (MMST) mapping, the theory requires no additional projection operators onto the space of physical states. When treated under a quasiclassical approximation, we show that the resulting dynamics is equivalent to that generated by the MMST Hamiltonian. What differs is the value of the zero-point energy parameter as well as the initial distribution and the measurement operators. For various spin-boson models the results of our method are seen to be a significant improvement compared to both standard Ehrenfest dynamics and linearized semiclassical MMST mapping, without adding any computational complexity. 13 pages, 5 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|