Dissociative ionization of methane in an elliptical pulse shaped laser field

The effect of strong femto-second laser pulses on the dissociation probability of methane has been investigated analytically in various arrangements. The ellipticity dependence of the dissociation probability at intensities from 1014 W cm−2 to 1016 W cm−2 for Ti:Sapphire laser is presented. A reliable calculation of the dissociation probability based on 3D time-dependent Schrodinger equation with an improved model of time-dependent density-functional theory is presented. These calculations are carried out for three different cases of elliptically polarized laser pulse, optimum convolution of dual short pulses, and two-color mixed nonresonant laser pulses. It is found that the rescattering contribution of the laser pulses to the fragmental yields is more remarkable for ε = 0.2, at 1015 W cm−2 laser intensity. Furthermore, by using the dual pulses combination for three proposed conditions, extracted by semi-classical approach, the dissociation rates up to 78% is achieved. In addition, by using a two-color mixed laser pulse, the total dissociation probability is improved up to 50% in comparison to a single pulse.