Laser-induced control of (multichannel) intracluster reactions

Abstract

An experimental and theoretical study on the excited Ba ⋯ FCH3(A) photodissociation yield as a function of the excitation laser fluence is reported. Experimentally, it was found that the two-photodissociation channel yields, i.e. the reactive BaF and non-reactive Ba* products, increased exhibiting a similar behaviour, as the laser fluence changed from 0.2 up to ca. 4 mJ/cm2. Beyond this value the BaF yield levels off and the Ba* decreases over the 4-7 mJ/cm2 range. The theoretical simulation of the excited state electron-ion dynamics within the time-dependent density functional theory revealed that the reactive channel dominated the photofragmentation dynamics as it occurs within a femtosecond time scale and became accelerated as the photodissociation laser fluence increased. By contrast, the non-reactive channel only manifested for low laser fluences at the nano/picosecond time regime resulted inactive as the laser fluence increased. A simple scheme to control the dynamics of the intracluster multichannel reaction is suggested in which the slowest the channel the easiest to close it as the excitation laser power increases.