Doubly charged ion mass spectra: V—Oxygen containing hydrocarbons

Abstract

AbstractDoubly charged ion mass spectra were obtained for 46 low molecular weight oxygen containing compounds. A double focusing Hitachi RMU‐7L mass spectrometer, operated at 3.2 kV accelerating voltage, was used to measure spectra for aliphatic alcohol, ketone, ether, aldehyde, ester and acid molecules, as well as several aromatic oxygen containing compounds. In general, the spectra were dominated by fragment ions which resulted from extensive H loss and CC bond rupture as well as O elimination from the doubly charged molecular ions. Total product ion intensities from doubly charged ion spectra of aliphatic oxygen containing compounds were approximately 1% of the corresponding total ion intensity in the benzene doubly charged ion spectrum. Appearance energies for forming prominent doubly charged molecular and fragment ions were determined. Measured values ranged from 26 to 45 eV. A geometry optimized quantum mechanical SCF treatment was used to compute the energies, charge densities and structures for several of these oxygen containing doubly charged ions.