PII: S0301-0104(98)00091-3
Copyright © 1998 Elsevier Science B.V. All rights reserved

Ultrafast laser control of vibrational dynamics for a two-dimensional model of HONO in the ground electronic state: separation of conformers, control of the bond length, selective preparation of the discrete and the continuum states

M. Oppel and G. K. Paramonov¹

Institut für Physikalische und Theoretische Chemie, Freie Universität Berlin, WE 3, Takustrasse 3, 14195 Berlin, Germany

Received 13 November 1997. Available online 8 October 1998.

Abstract

Selective excitation of the vibrational bound and the continuum states, controlled by subpicosecond infrared (IR) laser pulses, is simulated within the Schrödinger wave function formalism for a two-dimensional model of the HONO molecule in the ground electronic state. State-selective excitation of the OH bond is achieved by single optimal laser pulses, with the probability being 97% for the bound states and more than 91% for the resonances. Stable, long-living continuum states are prepared with more than 96% probability by two optimal laser pulses, with the expectation energy of the molecule being well above the dissociation 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 are demonstrated. Laser separation of spatial conformers of HONO in inhomogeneous conditions occurring on an anisotropic surface or created by a direct current (DC) electric field is analysed. The relative yields of target conformers may be very high, ranging from 10 to , and the absolute yields of up to 40% and more are calculated.

¹Permanent address: National Academy of Sciences of Belarus, Institute of Physics, Skaryna ave. 70, 220602 Minsk, Republic of Belarus.