PHOTOIONIZATION MASS-SPECTROMETRIC STUDY OF CH3OF

The vacuum ultraviolet photoionization mass spectrum of CH3OF displays a prominent parent ion peak, whose adiabatic onset is 11.340 +/- 0.008 eV, although much lower energy fragmentation processes (CH2O+ + HF, 8.0 eV; CH2OH+ + F, 9.3 eV) are possible. These lower energy processes have very low intensity. Two higher energy processes, to CH3+ + OF and CH2O+ +H +F, are observed. Their thresholds are used to determine DELTA-H(f0)0 (CH3OF) greater-than-or-equal-to - 23.0 +/- 0.7 kcal/mol, or D0 (CH3O-F) less-than-or-equal-to 47.4 +/- 1.2 kcal/mol. CH2OF+ is a significant fragment, whose appearance energy leads to DELTA-H(f0)0 (CH2OF+) almost-equal-to 215.1 +/- 0.8 kcal/mol.