Observation of time dependent relaxation effects in the photoelectron spectra of some metal carbonyls

✍ Scribed by D.S. Rajoria; L. Kovnat; E.W. Plummer; W.R. Salaneck

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 475 KB
• Volume: 49
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(77)80442-9

✦ Synopsis

Photcelectron rneasurements on transition metal wrbonyls in the gas phase were made at various photon energïes. Satellite peaks on the low kinetic energy side of the valrnce orbitals are observed and are attributed to shake up of the CO derived lerels. The variation of the ïntensity of the shake up, relative to the main peak with the kinetic energy at which the shake up peaks are observed. provides evidente for time dependent re!a..ation of the final state. This data indicates that the shake up intensity is constant for kinetic energies greater than = 20 ev. In this letter we report the results of a study of the low kinetic energy satellite structure on the prirnary photoemission lines in the photoelectron spectra of a range of metal carbonyls. These peaks are the shake up of the CO derived orbitals. The spectra were obtained at various photon enzrgies (21.2 eV, 40.8 eV, and 1253.7 eV) leading to the observation that the intensity of the shake up peaks relative to their respective rnain peaks is dependent upon the excitation energy. This provides evidente of time dependent relaxation of the molecule during ionïzation. The ionization and relaxation process can be understood by invokïng the role ofa time scale [l]. Meldner and Perez [2] have given a theory of gas phase atomic relaxation energies and relaxation times in adiabatlp and sudden limits. The theory has been extended to metals by Gadzuk and Sunjic [3]_ According to them [2,3] the time required for the collective response to the creation of a positive hole is determined by the kïnetic energy of the excited electron. As the kïnetic