The Use of HAM/3 in Interpreting the Oxygen K Emission Spectrum from Oxalate and Carbonate Anions

Molecular x-ray emission spectroscopy (XES), as other valence electron spectroscopic techniques, often yields spectra which may consist of no more than a few close lying or overlapping broad bands representing a relatively large number of active transitions. Oxygen K emission spectra often fall into this category even if the instrumental resolution is quite excellent (0.1-0.5 eV) simply because the natural halfwidths of the transitions may be of the order of 0.5 to 2 cV, and the transitions themselves may be very close (0.1 to 0.5 eV) to each other. Thus, deciphering a deceptively simple spectrum may be a difficult task. Aside from the correlation of the XES results with photoelectron data, it is highly desirable to have on hand reliable but inexpensive theoretical methods of calculating the eigenvalues and eigenvectors associated with the various molecular orbitals. In this report we show that HAM/3 developed by isbrink and coworkers(l) is, indeed, a useful and very inexpensive method for interpreting some XES results.