Theoretical study of finite temperature spectroscopy in van der Waals clusters. II Time-dependent absorption spectra

Florent Calvo (1) , Fernand Spiegelman (1) , D. J. Wales

1 LPQ - Laboratoire de Physique Quantique

Using approximate partition functions and a master equation approach, we investigate the statistical relaxation toward equilibrium in selected CaAr$_n$ clusters. The Gaussian theory of absorption (previous article) is employed to calculate the average photoabsorption intensity associated with the 4s^2-> 4s^14p^1 transition of calcium as a function of time during relaxation. In CaAr_6 and CaAr_10 simple relaxation is observed with a single time scale. CaAr_13 exhibits much slower dynamics and the relaxation occurs over two distinct time scales. CaAr_37 shows much slower relaxation with multiple transients, reminiscent of glassy behavior due to competition between different low-energy structures. We interpret these results in terms of the underlying potential energy surfaces for these clusters.

Domaines: Chimie-Physique [physics.chem-ph]; Agrégats Moléculaires et Atomiques [physics.atm-clus]

Florent Calvo, Fernand Spiegelman, D. J. Wales. Theoretical study of finite temperature spectroscopy in van der Waals clusters. II Time-dependent absorption spectra. Journal of Chemical Physics, 2003, 118, pp.8739. ⟨hal-00120714⟩