Calculation of reliable non-resonant Kα X-ray emission spectra of organic molecules and other small molecules

For reliable calculation of vertical ionization energies (VIEs) of both core and valence electrons of gas-phase organic molecules and other small molecules, we developed DFT procedures in 1999 and 2009. The difference between core and valence VIEs give the energies for X-ray emission spectra (XES). The dipole matrix elements between core and valence electrons required for calculation of the XES intensities are now easily available. The simple procedure for calculation of reliable XES is demonstrated by comparison with known XES for H2O(g), NH3(g), CO(g), CO2(g), N2(g), and NNO(g). Consequently, the XES of H2CO(g), formamide(g), 1-nitrosamine(g), N-methylformamide(g), 1-nitrosoaziridine(g), and oxirane(g) are predicted with confidence.