Quantum Control of NaI Predissociation in Subpicosecond and Several-Picosecond Time Regimes

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 1999-08, Vol.103 (32), p.6301-6308
• Main Authors: Hoki, K, Ohtsuki, Y, Kono, H, Fujimura, Y
• Format: Article
• Language: English
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp990894d

Laser pulses that enhance the predissociation reaction of NaI are theoretically studied based on a local control method. Two control schemes corresponding to two time regimes, one of subpicoseconds and one of a few picoseconds, are considered. For subpicosecond control, the pulse is designed to induce the Tannor−Rice pump−dump scheme, in which an intrapulse pump−dump process is predicted. The created wave packet has a high velocity to accelerate the nonadiabatic transition because of the Landau−Zener mechanism. On a longer time scale (several picoseconds), we employ a two-step control scheme. First, we use a variational procedure to determine the target wave packet that has the shortest lifetime at a given time. Then we calculate the control pulse to shape this target by a backward time propagation technique. Numerical results show that the wave packets generated by the control pulses are effective for accelerating the predissociation of NaI.