10.5 eV Photoionization Mass Spectroscopy

Abstract

Laser ionization is becoming an increasingly powerful tool in mass spectroscopy. By frequency tripling the third harmonic of a Nd:YAG laser (355 nm) in a mixture of xenon and argon, it is possible to produce coherent vacuum ultraviolet (VUV) radiation at 118 nm (10.5 eV) for laser ionization mass spectroscopy. 10.5 eV photoionization is a potentially powerful tool for soft ionization. Since 10.5 eV is close to the ionization energy of most molecules, little fragmentation should be induced. Since no resonant intermediate state is required in a one photon process the ionization efficiency should be relatively high and consistent for most compounds when compared to multiphoton ionization. The 10.5 eV mass spectra of aliphatic C8 compounds with functional groups which induce extensive fragmentation will be discussed in this presentation.