ULTRAFAST LASER CONTROL OF VIBRATIONAL DYNAMICS FOR A 2-DIMENSIONAL MODEL OF HONO2 IN THE GROUND ELECTRONIC-STATE - SEPARATION OF CONFORMERS, CONTROL OF THE BOND-LENGTH, SELECTIVE PREPARATION OF THE DISCRETE AND THE CONTINUUM STATES

Selective excitation of the vibrational bound and the continuum states , controlled by subpicosecond infrared (IR) laser pulses, is simulated within the Schrodinger wave function formalism for a two-dimensional model of the HONO2 molecule in the ground electronic state. State-sele ctive excitation of the OH bond is achieved by single optimal laser pu lses, with the probability being 97% for the bound states and more tha n 91% for the resonances. Stable, long-living continuum states are pre pared with more than 96% probability by two optimal laser pulses, with the expectation energy of the molecule being well above the dissociat ion threshold of the ON single bond, and its life-time being at least 100 ps. The length of the ON single bond can be controlled selectively : stretching and contraction by about 45% of its equilibrium length ar e demonstrated. Laser separation of spatial conformers of HONO2 in inh omogeneous conditions occurring on an anisotropic surface or created b y a direct current (DC) electric field is analysed. The relative yield s of target conformers may be very high, ranging from 10 to 10(8), and the absolute yields of up to 40% and more are calculated. (C) 1998 El sevier Science B.V. All rights reserved.