On the Applicability of the Caldeira-Leggett Model to Condensed Phase Vibrational Spectroscopy

Abstract

Formulating a rigorous system-bath partitioning approach remains an open issue. In this context the famous Caldeira-Leggett model that enables quantum and classical treatment of Brownian motion on equal footing has enjoyed popularity. Although this model is by any means a useful theoretical tool, its ability to describe anharmonic dynamics of real systems is often taken for granted. In this Letter we show that the mapping between a molecular system under study and the model cannot be established in a self-consistent way, unless the system part of the potential is taken effectively harmonic.Mathematically, this implies that the mapping is not invertible. This `invertibility problem' is not dependent on the peculiarities of particular molecular systems under study and is rooted in the anharmonicity of the system part of the potential.

revised version

References in corpus (3)

• Nuclear quantum effects in solids using a colored-noise thermostat
• Colored-noise thermostats à la carte
• Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations

Cited by in corpus (5)

• Application of the Mixed Time-averaging Semiclassical Initial Value Representation method to Complex Molecular Spectra
• Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations
• Discretized hierarchical equations of motion in mixed Liouville--Wigner space for two-dimensional vibrational spectroscopies of liquid water
• Simulating two-dimensional correlation spectroscopies with third-order infrared and fifth-order infrared--Raman processes of liquid water
• The Effect of Site-Specific Spectral Densities on the High-Dimensional Exciton-Vibrational Dynamics in the FMO Complex