Knowledge Bank

We present ab initio core ionization potentials and excitation thresholds for $CH4$, $CH3OH$, and some fluorinated methanes using Gaussian basis sets ranging in size from minimal to better than double zeta. We use the $\Delta$SCF procedure pioneered by P. $Bagus1$ to account for electronic relaxation. We pay particular attention to choosing Gaussian exponents and appropriate contractions to describe electronic relaxation. Efforts to calculate excitations from heavy atoms other than carbon will be discussed also.