GENERATION AND CHARACTERIZATION OF DIHYDROXYCARBENE, HO-C-OH, BY NEUTRALIZATION-REIONIZATION MASS-SPECTROMETRY

Dihydroxycarbene is produced in the gas phase by neutralization of the HO-C-OH+. radical cation which is formed by dissociative electron ionization of oxalic acid. Reionization approximately 0.3 mus later shows that HO-C-OH can survive intact and, thus, exists as a stable species with appreciable barriers for dissociation or rearrangement to formic acid (HCOOH). Within the time scale of the experiment, a small fraction of the carbene decomposes to H2O + CO. Comparison of the experimental results with ab initio theory shows that the dissociating HO-C-OH molecules are generated in the electronically excited triplet state, while the large amount of surviving carbene molecules is formed in the singlet ground state.