Nonadiabatic effects in multiphoton dissociation dynamics

✍ Scribed by O. Atabek

• Book ID: 101255354
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 212 KB
• Volume: 64
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1997)64:1<53::aid-qua6>3.0.co;2-0

✦ Synopsis

Nonadiabatic effects resulting from very short rise times few .

Ž 2 . femtoseconds of intense tens of TWrcm laser pulses may enhance in an unexpected way dissociation rates of molecules interacting with such radiation fields. Starting from a given initial vibrational level, the wavepacket describing the molecule-plus-field Ž system is spread over several resonances instead of a single one predicted when the . laser is adiabatically switched on interfering during the excitation process. The article reviews typical signatures of the time-dependent nonadiabatic behaviors of vibrational states' survival probabilities and of fragments' kinetic energy spectra. A H q molecular 2 ion irradiated by short intense laser pulses in the UV absorption wavelength regime is taken as an illustrative example. A possibility of dissociating the system using a single photon of 532 nm wavelength is devised, with the peculiarity that the energy carried by this photon is not enough for the fragmentation to occur. The suggested mechanism, which may be called below threshold dissociation, refers to a highly nonadiabatic switching on of the laser, leading to the temporal excitation of some resonances with efficient decay rates.