TY - JOUR A1 - Hartmann, Michael A1 - Heidenreich, Andreas A1 - Pittner, Jiřı́ A1 - Bonačić-Koutecký, Vlasta A1 - Jortner, Joshua T1 - Ultrafast Dynamics of Small Clusters on the Time Scale of Nuclear Motion JF - The Journal of Physical Chemistry A N2 - We present a theoretical study of the multistate dynamics of the Ag3-/Ag3/Ag3+ system on the time scale of nuclear motion, as explored by femtosecond pump−probe negative ion-to neutral-to positive ion (NENEPO) spectroscopy. The dynamics of the Ag3 cluster initiated from its linear transition state involves configurational relaxation, intracluster collision, and onset of IVR, resonant and dissipative IVR and vibrational equilibration, whose time scales were determined. Our analysis reveals that theory is essential for the elucidation of the rich dynamic information regarding geometrical change, completion of IVR, and vibrational coherence effects in the NENEPO femtosecond signals. KW - Physical chemistry KW - Nuclear motion Y1 - 1998 N1 - Volltext aus urheberrechtlichen Gründen nicht verfügbar. Fulltext due to copyright not available. VL - 102 IS - 23 SP - 4069 EP - 4074 ER - TY - JOUR A1 - Hartmann, Michael A1 - Pittner, Jiřı́ A1 - Bonačić-Koutecký, Vlasta A1 - Heidenreich, Andreas A1 - Jortner, Joshua T1 - Theoretical exploration of femtosecond multi-state nuclear dynamics of small clusters JF - The Journal of Chemical Physics N2 - We investigate ultrafast multi-state nuclear dynamics in a triatomic cluster. In particular, we explore how the intracluster nuclear dynamics of the Ag−3/Ag3/Ag+3 system is reflected in the femtosecond pump-probe negative ion-to neutral-to positive ion (NENEPO) signals. The nuclear dynamics is based on classical trajectories on the ground electronic adiabatic state potential hypersurfaces obtained from accurate ab initio quantum chemistry calculations. The nuclear dynamics of Ag3 initiated from the linear transition state involves distinct sequential processes of configurational relaxation to the triangular configuration, intracluster collisions, and the onset of IVR, resonant, and dissipative IVR, and vibrational equilibration. We determined the timescales for these processes and discussed their dependence on the initial cluster temperature. The Wigner representation of the density matrix was utilized to simulate the NENEPO-zero kinetic energy (NENEPO-ZEKE) signal and the total (integrated over the photoelectron energy) NENEPO signal. We show how geometrical change, completion of IVR and vibrational coherenceeffects can be identified in the NENEPO signals. A comparison of the calculated NENEPO signals with the available experimental data is presented. KW - Cluster dynamics KW - Femtosecond dynamics Y1 - 1998 N1 - Volltext aus urheberrechtlichen Gründen nicht verfügbar. Fulltext due to copyright not available. VL - 108 IS - 8 SP - 3096 EP - 3113 ER -