Emission, ground, and excited state absorption spectroscopy of Cr/sub 2/ isolated in Ar and Kr matrices

Journal Article · Thu Dec 15 04:00:00 EST 1983 · J. Chem. Phys.; (United States)

OSTI ID:5457782

Pellin, M J; Gruen, D M

Irradiation into either of the two resonance transitions of Cr atoms in Kr matrices results in strong bleaching of the atomic absorptions and simultaneous growth of two Cr/sub 2/ dimer bands. The lower energy band of Cr/sub 2/ at approx.470 nm is the well-known /sup 1/..sigma../sup +//sub u/ ..-->.. /sup 1/..sigma../sup +//sub g/ transition. The higher energy band at approx.340 nm we assign to the /sup 1/Pi/sub u/ reverse arrow /sup 1/..sigma../sup +//sub g/ transition which occurs at almost the same energy as, and is therefore obscured by, the y/sup 7/P/sup 0/ reverse arrow a/sup 7/S transition of normally present Cr atoms in Kr (and Ar) matrices. Laser induced fluorescence from the approx.470 nm band gives a broad, featureless emission presumably because of extensive predissociation after cage relaxation of the excited /sup 1/..sigma../sup +//sub u/ state. Emission after excitation of /sup 1/Pi/sub u/ reverse arrow /sup 1/..sigma../sup +//sub g/ transition yields a four member progression with spacing of approx.240 cm/sup -1/. The spectrum is consistent with emission from a /sup 3/..sigma../sub g/ ''trap'' level to a lower lying /sup 3/..sigma../sub u/ state, approx.8000 cm/sup -1/ above ground. An energy level diagram of the Cr/sub 2/ molecule is presented which incorporates all of the spectroscopic information available on the dimer.

• Research Organization: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5457782
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 79:12; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ARGON
CHROMIUM
DIMERS
ELEMENTS
EMISSION SPECTRA
ENERGY LEVELS
EXCITED STATES
FLUIDS
FLUORESCENCE
GASES
KRYPTON
LUMINESCENCE
MATRIX ISOLATION
METALS
MOLECULES
NONMETALS
RARE GASES
SPECTRA
TRANSITION ELEMENTS