Negative-ion mass spectrometric study of ion-pair formation in the vacuum ultraviolet. VI. CH3X→X−+CH+3 (X=F, Cl, Br)

Publisher Website
Google Scholar
Abstract
Ion‐pair formation from photoexcited halomethanes, CH3X*→X−+CH+3 (X=F, Cl, Br) has been studied by measuring photodissociation efficiency curves of X− using synchrotron radiation in the 9.9–27.5 eV photon energy range. A new spectral feature is observed in each of the curves near the threshold for the removal of an na1 electron from CH3X (n=4, 6, and 8, respectively, for CH3F, CH3Cl, and CH3Br ). This feature, composed of two or three peaks in each case, is interpreted as resulting from photoexcitation to the Rydberg states converging to CH3X+(C̃ 2A1), which then predissociate into ion pairs through avoided potential energy surface crossings. The interpretation is based on the results of the inner‐shell electron energy loss study by Brion and co‐workers and the photoabsorption study by Hochmann and co‐workers. Peak features are also observed in the X− efficiency curves near the ionization threshold for CH3X+(X̃ 2E). The origins of these peaks are also discussed.

This publication has 19 references indexed in Scilit: