where σtot is the total photodetachment cross-section, P2(x) is the second order Legendre polynomial,  Is the angle of the photoelectron velocity vector relative to the laser polarization axis, and  is the anisotropy parameter, which ranges between -1 for perpendicular and +2 for parallel detachment. The variation of the anisotropy parameter as a function of eKE reflects the symmetry and angular momentum of the orbital from which the electron is detached.