Resonant two-photon autoionization of H2. III. Effect of laser bandwidth and ac Stark shift on photoelectron angular distribution and line shape of the intermediate state.

In the case of resonant two-photon autoionization of ${\mathrm{H}}_{2}$, the influence of laser bandwidth on the photoelectron angular distribution is seen to be large at lower intensities (\ensuremath{\sim}${10}^{6}$ W/${\mathrm{cm}}^{2}$), but gradually disappears towards higher intensities. At very high intensities (\ensuremath{\sim}${10}^{12}$ W/${\mathrm{cm}}^{2}$), the ac Stark shift of the resonant intermediate state is found to affect the distribution significantly. It has also been found that the Stark-shifted line shape of the intermediate state tends to be symmetrical around zero detuning on increasing the laser bandwidth.