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Nonadiabatic effects in multiphoton dissociation dynamics
Author(s) -
Atabek O.
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)64:1<53::aid-qua6>3.0.co;2-0
Subject(s) - excitation , dissociation (chemistry) , atomic physics , laser , chemistry , fragmentation (computing) , wave packet , femtosecond , wavelength , photon , ion , kinetic energy , physics , optics , quantum mechanics , computer science , operating system , organic chemistry
Nonadiabatic effects resulting from very short rise times (fewfemtoseconds) of intense (tens of TW/cm 2 ) laser pulses mayenhance in an unexpected way dissociation rates of molecules interactingwith such radiation fields. Starting from a given initial vibrationallevel, the wavepacket describing the molecule‐plus‐field system is spreadover several resonances (instead of a single one predicted when the laseris adiabatically switched on) interfering during the excitation process.The article reviews typical signatures of the time‐dependent nonadiabaticbehaviors of vibrational states' survival probabilities and offragments' kinetic energy spectra. A H 2 + molecular ion irradiated by short intense laser pulses in the UV absorptionwavelength regime is taken as an illustrative example. A possibility ofdissociating the system using a single photon of 532 nm wavelength isdevised, with the peculiarity that the energy carried by this photon is notenough for the fragmentation to occur. The suggested mechanism, which maybe called below threshold dissociation, refers to a highly nonadiabaticswitching on of the laser, leading to the temporal excitation of someresonances with efficient decay rates. © 1997 John Wiley &Sons, Inc. Int J Quant Chem 64 : 53–61, 1997