On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics; Quantum liquid water

Ivanov, S. D.*; Witt, A.*; Shiga, Motoyuki   ; Marx, D.*

Centroid molecular dynamics, CMD, is a popular method to extract approximate quantum dynamics from path integral simulations. Here we provide evidence that for condensed phases, and in particular for liquid water, CMD produces pronounced artificial red-shifts for high-frequency vibrations such as the OH stretching band. This peculiar behavior intrinsic to the CMD method is improved after applying a simple "harmonic curvature correction".