Generalized oscillator-strength calculations for some low-lying excited states ofH2using a high-accuracy configuration-interaction wave function

1993 ◽  
Vol 48 (1) ◽  
pp. 166-172 ◽  
Author(s):  
J. W. Liu ◽  
S. Hagstrom
Keyword(s):  
Wave Function ◽  
Oscillator Strength ◽  
Excited States ◽  
Configuration Interaction ◽  
High Accuracy ◽  
Generalized Oscillator

The calculation of atomic oscillator strengths: the lithium atom revisited

1992 ◽  
Vol 70 (2) ◽  
pp. 456-463 ◽  
Author(s):  
A. W. Weiss
Keyword(s):  
Oscillator Strength ◽  
Excited States ◽  
Configuration Interaction ◽  
Lithium Atom ◽  
Laser Excitation ◽  
Oscillator Strengths ◽  
Excitation Energies ◽  
Accurate Evaluation ◽  
Theoretical Predictions ◽  
Configuration Interaction Calculations

Extensive configuration interaction calculations have been done for the ground and first excited states of neutral lithium and singly ionized beryllium. While the calculations reproduce the ionization and excitation energies to within 3 cm−1 for Li and 10 cm−1 for Be+, the main purpose of this work is the accurate evaluation of the 2s–2p resonance line oscillator strength. The calculated value of 0.7478 agrees to within less than 1% with the very accurate laser excitation lifetime measurement of 0.7416 ± 0.0012. However, internal consistency checks of the accuracy of these calculations suggest that more precise calculations are unlikely to reduce this discrepancy significantly. Furthermore, when placed together with other independent calculations that should be of comparable, if not better, accuracy, all theoretical predictions strongly indicate an f-value of 0.7475 ± 0.0010, which differs from the experiment by 4 experimental standard deviations. Keywords: configuration interaction, correlation, oscillator strength.

Ab initio MRD-CI Study of the Electronic Spectrum of Tribromomethanol Br3COH and the Photofragmentation along Br–C and C–O Cleavage

2003 ◽  
Vol 217 (3) ◽  
pp. 241-254
Author(s):  
M. Mühlhäuser
Keyword(s):  
Energy Range ◽  
Ab Initio ◽  
Electronic Spectrum ◽  
Oscillator Strength ◽  
Excited States ◽  
Atmospheric Chemistry ◽  
Configuration Interaction ◽  
Reference Configuration ◽  
Triplet States ◽  
Configuration Interaction Calculations

AbstractMulti reference configuration interaction calculations are carried out to compute the electronic spectrum of tribromomethanol Br3COH. The first dipole-allowed transitions are computed at 5.0 eV (11A″ ← X1A′) and 5.4 eV (21A″ ← X1A′) followed by three transitions at 5.5 eV (21A′ ← X1A′) and 6.1 eV (31A′ ← X1A′, 31A″ ← X1A′). The largest oscillator strength (f = 0.08) is obtained for the σ → σ* type excitation 31A″ ← X1A′ computed around 6.1 eV. The corresponding triplet states are also given. Five low-lying excited states in the energy range between 4.5 eV and 5.5 eV are found to be highly repulsive for Br–C elongation, leading to Br2CHOH (X2A′) and Br (X2P), so that tribromomethanol Br3COH is expected to be important for atmospheric chemistry as reservoir of Br radicals. Photodissociation along C–O cleavage resulting in Br3C (X2A′) and OH (X2Π) has to overcome a barrier of about 0.7 eV because the low-lying excited states 11A″, 13A′ and 13A″ become repulsive only after elongating the C–O bond by about 0.45 Å.

ENERGY, OSCILLATOR STRENGTH AND HYPERFINE STRUCTURE OF THE LOW-LYING EXCITED STATES FOR Be-LIKE SYSTEM

2003 ◽  
Vol 14 (05) ◽  
pp. 549-560 ◽  
Author(s):  
FEI WANG ◽  
BINGCONG GOU ◽  
XIAOLI WU ◽  
LIHONG HAN
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Variational Method ◽  
Hyperfine Structure ◽  
Oscillator Strength ◽  
Excited States ◽  
Oscillator Strengths ◽  
Transition Rates ◽  
Isoelectronic Sequence ◽  
Relativistic Corrections

The Rayleigh–Ritz variational method is carried out with a multiconfiguration-interaction wave function and restricted variational method to obtain the relativistic energies of the 1s22s2p 1Po , 1s22s2p 3Po , and 1s22p23P states for the beryllium-like isoelectronic sequence (Z=4–10), including the mass polarization and relativistic corrections. The oscillator strengths and transition rates are also calculated. The results are compared with other theoretical and experimental data in the literature. The hyperfine structure of the low-lying excited states for this system is also explored.

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