Photoionization Studies on Boric Acid with Synchrotron Radiation

Photoionization mass spectromeric study of B（OH)₃ with a vacuum ultraviolet synchrotron radiation source is reported. The photoionization mass spectrum and the potoionization efficiency curves of B（OH）₃⁺ and its three fragmental ions were measured. The ionization potential of B（OH)₃ was determined directly from the photoion threshold and the appearance potentials of the fragmental ions B（OH）₂⁺, H⁺, OH⁺ were obtained according to the curves, and some bond dissociation energies were derived from them. In addition, the possible passways of dissociative photoionization of B（OH)₃ with synchrotronradiation as light source have been analyzed.