Evaluation of the nondiabaticity of quantum molecular dynamics with the dephasing representation of quantum fidelity

Abstract

We propose an approximate method for evaluating the importance of non-Born-Oppenheimer effects on the quantum dynamics of nuclei. The method uses a generalization of the dephasing representation (DR) of quantum fidelity to several diabatic potential energy surfaces and its computational cost is the cost of dynamics of a classical phase space distribution. It can be implemented easily into any molecular dynamics program and also can utilize on-the-fly ab initio electronic structure information. We test the methodology on three model problems introduced by Tully and on the photodissociation of NaI. The results show that for dynamics close to the diabatic limit the decay of fidelity due to nondiabatic effects is described accurately by the DR. In this regime, unlike the mixed quantum-classical methods such as surface hopping or Ehrenfest dynamics, the DR can capture more subtle quantum effects than the population transfer between potential energy surfaces. Hence we propose using the DR to estimate the dynamical importance of diabatic, spin-orbit, or other couplings between potential energy surfaces. The acquired information can help reduce the complexity of a studied system without affecting the accuracy of the quantum simulation.

5 pages, 3 figures, section Theory extended(v2), small textual improvements(v2), added reference(v2 & v3), added acknowledgement(v3), submitted to J. Chem. Phys

References in corpus (2)

• Dephasing representation of quantum fidelity for general pure and mixed states
• Efficient evaluation of accuracy of molecular quantum dynamics using dephasing representation

Cited by in corpus (18)

• On-the-fly ab initio semiclassical evaluation of absorption spectra of polyatomic molecules beyond the Condon approximation
• Semiclassical Approach to Photophysics Beyond Kasha's Rule and Vibronic Spectroscopy Beyond the Condon Approximation. The Case of Azulene
• On-the-fly ab initio semiclassical evaluation of electronic coherences in polyatomic molecules reveals a simple mechanism of decoherence
• Relation of exact Gaussian basis methods to the dephasing representation: Theory and application to time-resolved electronic spectra
• Efficient geometric integrators for nonadiabatic quantum dynamics. II. The diabatic representation
• Quantum to classical transition in the work distribution for chaotic systems
• Measuring nonadiabaticity of molecular quantum dynamics with quantum fidelity and with its efficient semiclassical approximation
• Assessing mixed quantum-classical molecular dynamics methods for nonadiabatic dynamics of molecules on metal surfaces
• Efficient geometric integrators for nonadiabatic quantum dynamics. I. The adiabatic representation
• Beating the efficiency of both quantum and classical simulations with semiclassics
• Evaluation of the importance of spin-orbit couplings in the nonadiabatic quantum dynamics with quantum fidelity and with its efficient "on-the-fly" ab initio semiclassical approximation
• Improving the accuracy and efficiency of time-resolved electronic spectra calculations: Cellular dephasing representation with a prefactor
• How important are the residual nonadiabatic couplings for an accurate simulation of nonadiabatic quantum dynamics in a quasidiabatic representation?
• High-order geometric integrators for representation-free Ehrenfest dynamics
• Optimizing adiabaticity in quantum mechanics
• Semiclassical approach to fidelity amplitude
• Nonadiabaticity of Quantum harmonic oscillators
• Breaking the exponential wall in classical simulations of fidelity