Anharmonic INS and IR Spectra

CPMD simulations were performed at constant volume and T = 84 K, which is the average temperature of different experimental studies of crystalline H502+C104 [103-105], In dynamic runs a fictitious electron mass of 600 au and a time step of 0,12 fs were employed. The BLYP equilibrium geometry was used as a starting point. The trajectory length was 4.5 ps. 

The time step was 0.5 fs and the trajectory length was 3 ps. Theoretical spectra were calculated by averaging over two trajectories, obtained with opposite signs of the starting velocities. 

According to experiment [104] shown at the top of Fig. 9.8 the IR intensities of the C104 fundamentals ( 1000 cm i) are lower than those of the asymmetric stretches of the fragment, while the present calculations using the 

Comparison of the theoretical INS and IR spectra of the H502+C104 crystal shows that the band around 1150 cm i is much broader in the IR spec- 

Summarizing, the assignment of bands in the INS and IR spectra of the H5O2+ ion in the H502+C104 crystal may be done in harmonic approximation. 

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