Dynamics of a multimode system coupled to multiple heat baths probed by two-dimensional infrared spectroscopy.
Reduced equation of motion for a multimode system coupled to multiple heat baths is constructed by extending the quantum Fokker-Planck equation with low-temperature correction terms (J. Phys. Soc. Jpn. 2005, 74, 3131). Unlike such common approaches used to describe intramolecular multimode vibration as a Bloch-Redfield theory and a stochastic theory, the present formalism is defined by the molecular coordinates. To explore the correlation among different modes through baths, we consider two cases of system-bath couplings. One is a correlated case in which two modes are coupled to a single bath, and the other is an uncorrelated case in which each mode is coupled to a different bath. We further classify the correlated case into two cases, the plus- and minus-correlated cases, according to distinct correlation manners. For these, one-dimensional and two-dimensional infrared (2D-IR) spectra are calculated numerically by solving the equation of motion. It is demonstrated that 2D-IR spectroscopy has the ability to analyze the correlation of fluctuation-dissipation processes among different modes.
Ishizaki
Akihito
A
Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. ishizaki@kuchem.kyoto-u.ac.jp
Tanimura
Yoshitaka
Y
D006358:Hot Temperature; D008956:Models, Chemical; D009038:Motion; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013696:Temperature