Inner shell excitation and dissociation of condensed formamide

Ikeura, Hiromi*; Sekiguchi, Tetsuhiro  ; Kitajima, Yoshinori*; Baba, Yuji  

Carbon and nitrogen K-shell excitation and dissociation of condensed formamide at 96 K were studied by near edge X-ray absorption fine structure (NEXAFS) recorded by total electron yield (TEY), total ion yield (TIY) and photon-stimulated desorption (PSD) yield of H+ measurements. It was found that electronic transitions from the C1s or the N1s to the *(C-H) and/or (N-H) enhanced ion yield of H+ from the C-H and/or N-H functional group. This selective dissociation indicates that the corresponding unoccupied molecular orbital has an antibonding character of the C-H and/or N-H. To investigate the molecular orientation of condensed formamide, incidence-angle-dependent TEY-NEXAFS spectra were measured. The CNO plane of the adsorbed formamide molecule is determined to be tilted away from the surface by an averaged angle of about 42 degrees.