No abstract

No abstract

Experimental and theoretical pump-probe studies are performed for the K 2 molecule. Special molecular spectroscopic properties combined with the dynamics induced by "femtosecond state preparation" facilitate the transition from pump-probe to control spectroscopy. Hereby, the intensity of the laser field serves as a control parameter in the observed multiphoton processes. In the monitored transient ion signal we can distinguish the effect of two processes, i.e., multiphoton ionization (MPI) and resonant impulsive stimulated Raman scattering (RISRS). As a consequence, the temporal evolution of the ion signal reflects the induced dynamics of either the first excited state A 1 Σ u + or the ground state X 1 Σ g + of the potassium dimer.

plus remain reasonably constant when the concentration of the heptanes-plus fraction is decreased by a factor of approximately 2. The effect of a decrease in the heptanesplus fraction at the concentrations studied serves mainly to extend the pressure region over which these ratios are defined. This trend could be completely reversed with a continued decrease in the heptanes-plus concentration. Decreasing the amount of the heptanes-plus fraction in this system does have a slight effect on the equilibrium ratios of the intermediate components, ethane through hexanes; the net effect is a small increase at the higher pressures.

No abstract