Computational study of the structures and photoelectron spectra of gas-phase nitrosamines: Dimethylnitrosamine, N-nitrosopyrrolidine and 1-nitrosoaziridine

The structures of three nitrosamines in gas phase are optimized with various levels of theory available in the Gaussian program. For dimethylnitrosamine and N-nitrosopyrrolidine, the reported rotational constants from microwave spectra let us select the best optimized geometry. For 1-nitrosoaziridine, however, we decide to choose the geometry optimized by CCSD/cc-pVTZ method. At these geometries, the photoelectron spectra are calculated with established methods using the Amsterdam Density Functional program. The calculated ionization energies of valence electrons agree well with available experimental data and provide values for the missing photoelectron data. On the other hand, the computed core-electron binding energies of dimethylnitrosamine agree well with the values from 1975 X-ray solid-state photoelectron spectra after adding the work function. The predicted values for N-nitrosopyrrolidine and 1-nitrosoaziridine must wait for experiments for confirmation.