Structures of products from positive ion-molecule reactions by means of vibrational spectroscopy.
Examples of various approaches to determining gaseous ion structures are described. Two cases are presented in which infrared multiple photon dissociation (IRMPD) spectroscopy provides characteristic information. Comparison with DFT-calculated normal modes differentiates isomers. The IRMPD spectrum of the even-electron C(8)D(8)F(+) product ion from the ion-molecule reaction of CF(3)(+) with perdeuterated acetophenone exhibits a degree of resolution sufficient to identify C(6)D(5)CFCD(3)(+) and rule out ring-fluorinated isomers. The dimerization of phenylacetylene with its molecular ion has been explored, with the conclusion that a mixture of product ions is formed. The best match to the experimental spectrum is achieved by superimposing the bands calculated for ionized 1-phenylazulene and ionized 1,2-diphenylcyclobutadiene.
Oomens
Jos
J
FOM Institute of Plasma Physics, Rijnhuizen, Edisonbaan 14, Nieuwegein, The Netherlands.
Morton
Thomas Hellman
TH