Infrared-laser-pulse control of bond- and state-selective excitation, dissociation and space quantization: application to a three-dimensional model of HONO2 in the ground electronic state

Selective control over the vibrational excitation and space quantization of the dissociation fragments by optimally designed linearly polarized and sh aped infrared (IR) laser pulses of the picosecond (ps) and subpicosecond du ration is demonstrated by means of quantum-dynamical simulations within the Schrodinger wave-function formalism for a three-dimensional (3-D) model of HONO2 in the ground electronic state, wherein the OH and the ON single-bon d stretches are explicitly treated, together with the bending angle between them, on the basis of the ab initio defined 3-D potential-energy surface a nd dipole function. The high-lying zeroth-order vibrational states of the O H bond are prepared selectively both below and above the dissociation thres hold of the ON single bond, and demonstrate a quasi-periodic oscillatory be haviour, manifesting intramolecular vibrational energy redistribution (IVR) on the picosecond timescale. Selective breakage of the ON single bond in H ONO2 with more than 97% probability is demonstrated, along with control of the space quantization of the dissociation fragments: the OH fragments rota ting clockwise, OH(c), and anticlockwise, OH(a), are prepared selectively, with the OH(a)/OH(c) branching ratio being as high as 10.975. The results o btained show that optimally designed strong and short IR-laser pulses can c ompete against IVR and manipulate vibrational excitation and dissociation o f polyatomic molecules.