Band Shape of Photoelectron Spectrum and Potential Energy Curve for Alkylamine

• Published in: Bulletin of the Chemical Society of Japan Vol. 60; no. 1; pp. 9 - 18
• Main Authors: Takahashi, Masao, Watanabe, Iwao, Ikeda, Shigero
• Format: Journal Article
• Language: English
• Published: Tokyo The Chemical Society of Japan 01.01.1987; Chemical Society of Japan
• Subjects: Atomic and molecular physics; Exact sciences and technology; Molecular properties and interactions with photons; Photoelectron spectra; Physics; Potential energy curve; Substituent effect; Franck Condon factor; Ab initio method; Photoelectron spectrum; Theoretical study; Experimental study; Amine; Spectral line profile; Saturated aliphatic compound; Gaseous state; Ionization potential; Organic compounds; Conformation
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.60.9

Accurate measurements of UPS and ab initio potential energy calculations have been carried out for ammonia and several alkylamines to interpret the band shape of the UPS. Theoretical photoelectron band shape was obtained by a simple Franck–Condon approach. The calculation predicted very well the alkyl substitution effects on the ionization potentials and on the band widths of the first bands in UPS for the alkylamines. The following conclusions were obtained by comparing these theoretical photoelectron bands with experimental ones. The threshold ionization potential observed in the UPS is not always thermodynamically adiabatic ionization energy, but it can be subject to hot bands. Adiabatic ionization potential IPa of ammonia is concluded to be 10.08 eV. And the values of IPa for a series of alkylamines are evaluated by taking account of molecular vibrational frequency for the neutral state.