Dissociation of NO2 in femtosecond intense fields

Experimental investigations on the dis-sociation and ionization processes of NO2 in intensefields at wavelengths of 810, 405 and 270 nm, arepresented. The ratios of NO +2 /NO + are found to beindependent of the laser intensity at these threewavelengths, but show strong dependence on thewavelengths. Longer wavelength produces a largerparent-ion yield in comparison with 405 nm. Peakprofiles of all the fragment ions clearly show little ki-netic energy releasing during the dissociation. Frag-ment ions are suggested to be produced from disso-ciation of the field ionized parent ions. Our resultsindicate that laser pulse wavelengths are the mostimportant parameters in ionization-fragmen- tationprocess of polyatomic molecules in intense field otherthan the laser intensity.