Photodissociation and photoionization and their branching ratio in bisbenzene chromium

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.465786· OSTI ID:6368746

Penner, A; Amirav, A ^[1]; Tasaki, S; Bersohn, R ^[2]

---

1. School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978 Tel Aviv (Israel)
2. Department of Chemistry, Columbia University, New York, New York 10027 (United States)

Bisbenzene chromium (BBC) with an unusually low ionization potential, 5.45 eV is a model molecule to study phenomena near the ionization potential. A beam of BBC molecules cooled by a supersonic expansion was used to measure the absorption spectrum and the excitation spectra for ionization and Cr atom production. The uv spectrum is mainly a Rydberg series terminating at the ionization potential together with progressions in the symmetric benzene--Cr stretch. In the range from 320 to 282 nm, the region of a non-Rydberg absorption band, the excitation spectrum for Cr atom production is quite different from the absorption spectrum. In contrast, in the range 282--227 nm the excitation spectrum for Cr atom production is practically identical with the absorption spectrum. This identity suggests a close to 100% yield of Cr atoms. Near the ionization energy of BBC the yield of Cr atoms decreases while the ionization yield increases until a quite steady branching ratio of three Cr[sup +] ions to one Cr atom is reached. The rates of dissociation of excited BBC into Cr atoms are 0.70[plus minus]0.02[times]10[sup 6] s[sup [minus]1] and 4.2[plus minus]0.1[times]10[sup 6] s[sup [minus]1] at 279.8 and 248 nm, respectively.

• OSTI ID: 6368746
• Journal Information: Journal of Chemical Physics; (United States), Vol. 99:1; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BENZENE
PHOTOIONIZATION
CHROMIUM COMPOUNDS
ABSORPTION SPECTRA
COOLING
DISSOCIATION
EXCITATION
IONIZATION POTENTIAL
MOLECULAR BEAMS
RYDBERG STATES
SUPERSONIC FLOW
AROMATICS
BEAMS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUID FLOW
HYDROCARBONS
IONIZATION
ORGANIC COMPOUNDS
SPECTRA
TRANSITION ELEMENT COMPOUNDS
664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)