Time-dependent self-consistent harmonic approximation: Anharmonic nuclear quantum dynamics and time correlation functions

Real time quantum correlation functions. I. Centroid molecular dynamics of anharmonic systems

We investigate the accuracy of the recently proposed centroid molecular dynamics ~CMD! method @J. Cao and G. A. Voth, J. Chem. Phys. 100, 5106 ~1994!# in the presence of highly anharmonic steep short range repulsive potentials. Such potentials are often present in condensed phases and govern collisions between solvent particles. We compare the results of CMD simulations with exact quantum resul...

Time-dependent studies of reaction dynamics : a test of mixed quantum/classical time-dependent self-consistent Ðeld approximations

Two approaches for applying the quantum/classical time-dependent self-consistent Ðeld approximation to collinear reaction dynamics are investigated for a generic heavy plus lightÈheavy (A] HB) reaction. In the Ðrst, a single quantum/classical trajectory is run, and in the second a small ensemble of quantum/classical trajectories are used. In the latter case, we derive a multiple trajectory exte...

Quantum Dynamics in Classical Time Evolution of Correlation Functions

The time-dependence of correlation functions under the influence of classical equations of motion is described by an exact evolution equation. For conservative systems thermodynamic equilibrium is a fixed point of these equations. We show that this fixed point is not universally stable, since infinitely many conserved correlation functions obstruct the approach to equilibrium. Equilibrium can t...

Time-Dependent Statistical Mechanics 12. Quantum correlation functions

Quantum State Diffusion and Time Correlation Functions

In computing the spectra of quantum mechanical systems one encounters the Fourier transforms of time correlation functions, as given by the quantum regression theorem for systems described by master equations. Quantum state diffusion (QSD) gives a useful method of solving these problems by unraveling the master equation into stochastic trajectories; but there is no generally accepted definition...