Density functional theory study of the electron spectra of formamide vapor

The ionization and excitation spectra of the valence and core electrons of formamide in the gas phase are studied with density functional theory. The calculated ionization energies of both valence and core electrons agree very well with experiment, with an average absolute deviation of only 0.1 eV from experiment for all twelve MOs, and confirm the nonplanarity of formamide. The theoretical valence-electron absorption spectrum also agrees well with experiment. However, the inner-shell excitation spectra are not as well reproduced by the present calculations and require further study.