Open AccessPhotoionization study of Fe(CO)5 and Ni(CO)4
Author(s) -
Giuseppe Distefano
Publication year - 1970
Publication title -
journal of research of the national bureau of standards. section a. physics and chemistry
Language(s) - English
Resource type - Journals
eISSN - 2376-5704
pISSN - 0022-4332
DOI - 10.6028/jres.074a.019
Subject(s) - photoionization , ionization , ion , dissociation (chemistry) , fragmentation (computing) , nickel , electron ionization , chemistry , molecule , analytical chemistry (journal) , standard enthalpy of formation , photon energy , materials science , photon , physics , organic chemistry , chromatography , computer science , operating system , quantum mechanics
Photoionization yield curves from onset to 600Å, and ionization threshold values have been obtained for the ions Fe ( CO ) 5 + , Fe ( CO ) 4 + , Fe ( CO ) 3 + , Fe ( CO ) 2 + , Fe ( CO ) + , Fe + and CO + from iron penta-carbonyl, and for Ni ( CO ) 4 + , Ni ( CO ) 3 + , Ni ( CO ) 2 + , Ni ( CO ) + , Ni + , and CO + from nickel tetracarbonyl. From these curves, information on the ionization-fragmentation processes of Fe(CO) 5 and Ni(CO) 4 under photon impact, have been obtained. Differences in the threshold energies as determined by photon and by electron impact methods increase with the fragmentation. The appearance potentials and the heats of formation of the metal-ions, agree within 0.1 eV, with those calculated from thermochemical data. The average bond dissociation energy of the neutral molecule agrees within 0.02 eV, with the thermochemical values. The kinetic shift for the formation of Fe + and Ni + ions is very small. The Ni ion is most likely formed directly from the molecule ion rather than by a cascade fragmentation process.