NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Accurate ab initio calculations which demonstrate a 3 Pi u ground state for Al2The spectroscopic parameters and separations between the three low-lying X 3 Pi u, A 3 Sigma g -, and a 1 Sigma g + states of Al2 are studied as a function of both the one-particle and n-particle basis set. Approximate correlation treatments are calibrated against full Cl calculations correlating the six valence electrons in a double-zeta plus two d-function basis set. Since the CASSCF/MRCI 3 Pi u to 3 Sigma g - separation is in excellent agreement wtih the FCI value, the MRCI calculations were carried out in an extended (20s13p6d4f)/(6s5p3d2f) gaussian basis. Including a small correction for relativistic effects, the best estimate is that 3 Sigma g - state lies 174/cm above the 3 Pi u ground state. The 1 Sigma g + state lies at least 2000/cm higher in energy. At the CPF level, inclusion of 2s and 2p correlation has little effect on D sub e, reduces T sub e by only 26/cm, and shortens the bond lengths by about 0.02 a sub o. Further strong support for a 3 Pi u ground state comes from the experimental absorption spectra, since both observed transitions can be convincingly assigned as 3 Pi u yields 3 Pi g. The (2) 3 Pi g state is observed to be sensitive to the level of correlation treatment, and to have its minimum shifted to shorter rho values, such that the strongest experimental absorption peak probably corresponds to the 0 yields 2 transition.
Document ID
19880001284
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Bauschlicher, Charles W., Jr. (NASA Ames Research Center Moffett Field, CA., United States)
Partridge, Harry (NASA Ames Research Center Moffett Field, CA., United States)
Langhoff, Stephen R. (NASA Ames Research Center Moffett Field, CA., United States)
Taylor, Peter R. (Eloret Corp. Sunnyvale, CA., United States)
Walch, Stephen P. (Eloret Corp. Sunnyvale, Calif., United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1986
Subject Category
Solid-State Physics
Report/Patent Number
NASA-TM-89302
NAS 1.15:89302
Accession Number
88N10666
Funding Number(s)
CONTRACT_GRANT: NCC2-296
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available