Understanding the broadening of the HO Infra-Red spectrum through clustering of path integral molecular dynamics trajectories

Thomsen, B.  ; Shiga, Motoyuki   

We present the IR spectrum of the protonated water cluster HO calculated by using the Weight Averaged Approach (WAA), where the weights are found by clustering the structures found in a path integral molecular dynamics simulation. The WAA method was used to model the motions of nine low lying cluster relaxation modes in the protonated water cluster, which we were not able to include in a previous calculation of the spectrum of this cluster. It is expected that this procedure will result in a better reproduction of the broadening of the IR spectrum and might reveal the nature of one of the missing vibrational bands in the previous calculation.