Negative-ion photoelectron spectroscopy of acrylonitrile clusters containing a sodium atom

Cluster anions of a sodium atom with acrylonitrile molecules, Na(AN) _n^- (n = 0-6), have been studied by negative-ion photoelectron spectroscopy. In addition, theoretical calculations by using density functional theory have been performed to obtain optimized structures and vertical detachment energies. For Na(AN)^-, the spectrum can be explained by excitation of two different isomers of the anion. For Na(AN) ₃^-, a broad band is found in the photoelectron spectrum, whose profile is almost identical with those of previously reported photoelectron spectra of (AN)₃^- and a negative ion of chemically synthesized 1,3,5-cyclohexanetricarbonitrile (CHTCN) molecule. From this resemblance of band profiles, we conclude that oligomerization of (AN) ₃ takes place in Na(AN)₃^- and the CHTCN is formed as the intracluster reaction product.