PII: S0009-2614(99)01095-7
Copyright © 1999 Elsevier Science B.V. All rights reserved

Selective vibronic excitation and bond breaking by picosecond UV and IR laser pulses: application to a two-dimensional model of HONO₂

M. Oppel and G. K. Paramonov^{1, *}

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

Received 15 March 1999; revised 17 September 1999. Available online 3 January 2000.

Abstract

A new method to control a bond-selective dissociation is presented: first, an optimal UV laser pulse accomplishes vibrationally state-selective complete population transfer from the ground to the excited electronic state and, second, an optimal IR laser pulse induces an efficient bond-selective multiphoton dissociation. The method is demonstrated by means of computer simulation within the Schrödinger wavefunction formalism for a two-dimensional model of HONO₂ wherein the OH and ON single-bond stretches are treated explicitly. Selective breaking of the ON single bond is achieved on a picosecond timescale, with the dissociation probability being almost 100%. The proposed control scheme is much less demanding of the field strength of the dissociating IR laser as compared to that required for breaking the ON single bond solely in the ground electronic state.

¹On leave from the National Academy of Sciences of Belarus, Institute of Physics, Skaryna Ave. 70, 220602 Minsk, Republic of Belarus.

^*Corresponding author. Fax: +49-030-838-4792; e-mail: paramon@chemie.fu-berlin.de