Electronic structures of melatonin and related compounds studied by photoelectron spectroscopy

Mari Kubota, Tsunetoshi Kobayashi

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9 Citations (Scopus)


Melatonin is a hormone structurally regarded as being composed of a 5-methoxyindole group and an N-ethylacetamide group; its various physiological activities have attracted a great deal of attention recently. The gas phase He(I) photoelectron spectra of melatonin (M) and its related compounds including N-acetylserotonin have been studied with the aid of molecular orbital calculations. The first photoelectron spectral band group of compound M is ascribed to ionizations from the two π orbitals localized on the methoxyindole group. The second band group is quite complicated and is regarded as being composed of several bands. The lower energy part of the second band group is ascribed to the three orbitals relevant to the third highest occupied π orbital of 5-methoxyindole and the highest occupied π and the nC=O orbitals of N-ethylacetamide. The interactions among the three orbitals have been found to operate on the basis of the molecular orbital calculations; these interactions depend strongly on the conformations. The high energy end of the second band group is relevant to the π orbital mainly localized on the 5-methoxyindole group and is ascribed to the fourth highest occupied π orbital of 5-methoxyindole.

Original languageEnglish
Pages (from-to)165-178
Number of pages14
JournalJournal of Electron Spectroscopy and Related Phenomena
Issue number2-3
Publication statusPublished - 2003 Feb 1



  • He(I) photoelectron spectra
  • Melatonin
  • N-Acetylserotonin

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Radiation
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry

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