Ion yields of laser aligned CH3I and CH3Br from multiple orbitals

Abstract

We have measured the alignment influence on ion yields of CH3I and CH3Br molecules in the laser intensity regime from 1013W/cm2 to 1015W/cm2. The hexapole state-selection technique combined with laser induced alignment has been employed to obtain aligned (〈P2(cosθ)〉=0.7) and anti-aligned (〈P2(cosθ)〉=-0.1) CH3I and CH3Br molecules. The ratio of saturation intensities observed for the CH3I and CH3Br molecules with different alignments are simulated using a modified PPT model for molecules considering different orbitals and a good agreement has been achieved, indicating the contribution from multiple orbitals in the ionization.