ZEKE-PFI SPECTRA OF $AlNH_{3}$ AND $AlNH_{2}(CH_{3})$

Author Institution: Department of Chemistry, University of Kentucky; National Institute of Materials and Chemical Research, National Institute for Advanced Interdisciplinary ResearchThe aluminum complexes were prepared in a metal cluster source and identified with a time-of-flight mass spectrometer. The electronic spectra of the complexes were measured with single-photon ZEKE-PFI (zero electron energy pulsed field ionization) technique. The ZEKE spectrum of $AlNH_{3}$ shows vibronic transitions from two spin-orbit levels of the neutral ground electronic state, which allows the measurements of the following spectroscopic constants: ionization potential $(39746 cm^{-1})$, spin-orbit splitting $(58 cm^{-1})$, $Al-NH_{3}$ symmetric stretching frequencies $(\omega ^{+}_{3}= 339 cm^{-1}$, $\omega^{+}_{3} x^{+}_{3}= 3.1 cm^{-1}$, and $\nu_{3} = 227 cm^{-1})$, and Al-N symmetric bending frequency $(\nu^{+}_{6}= 557 cm^{-1})$. The ZEKE spectrum of $AlNH_{2}(CH_{3})$ displays at least four progressions, from which two vibrational modes (365 and $160 cm^{-1}$) may be identified