Ab initio configuration interaction calculations of ground state and lower excited states of Zn2 using optimized Slater-type wavefunctions

1997 ◽  
Vol 93 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Alfredo Aguado ◽  
Jose´ M. García de la Vega ◽  
Beatriz Miguel
Keyword(s):  
Ab Initio ◽  
Excited States ◽  
Configuration Interaction ◽  
Ground State ◽  
Slater Type ◽  
Configuration Interaction Calculations

The Electronic Spectrum and Structure of Tetrasulfur Dinitride

1983 ◽  
Vol 38 (1) ◽  
pp. 74-77 ◽  
Author(s):  
Michael H. Palmer
Keyword(s):  
Molecular Structure ◽  
Ab Initio ◽  
Electronic Spectrum ◽  
Excited States ◽  
Configuration Interaction ◽  
Configuration Interaction Calculations ◽  
Single Configuration ◽  
Virtual Orbitals

Abstract Ab initio configuration interaction calculations of the ground and singlet A′ and A″ excited states have been performed, with all possible single and double excitations from the 10 highest occupied orbitals to the lowest 17 virtual orbitals being included, the previous Cs symmetry molecular structure being used. Some of the states can be identified with excitation from individual occupied (SCF) orbitals to members of the virtual set, but some are not well represented by single configuration concepts. The results suggest that the three broad UV-spectral maxima observed in solution are not single excitations, but groups of excited states, with a total of 8 states. The closeness of some of these states makes positive assignment difficult. The most probable assignment is 455 nm (1 A″), 377 nm (2A″ + 1A′+ 2A′), ~ 277 nm (3A″ + 3A′), 232 nm (4A′ + 4A″).

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.

Ab Initio-Rechnungen zum F2-Molekül/ Different ab-initio calculations for the ground-state and some excited states of the F2-molecule

1973 ◽  
Vol 28 (5) ◽  
pp. 704-708 ◽  
Author(s):  
E. Kasseckert
Keyword(s):  
Ab Initio ◽  
Excited States ◽  
Ground State ◽  
Good Description ◽  
Basis Functions ◽  
Slater Type Orbitals ◽  
Slater Type ◽  
Ci Calculations ◽  
Potential Curves ◽  
Higher Excited States

For the ground-state and the lower lying excited states of the fluorine-molecule VB -CI calculations with Slater-type orbitals and SCF -CI calculations with contracted Gauß-Lobe functions have been carried out. The SCF -CI method yields a fairly good description of the ground-state. But it is rather difficult to decide whether the SCF -CI calculations of the excited states are accurate or not. The discussion of the potential-curves of some higher excited states leads to the conjecture that the experimentally observed orange band-systems may belong to two transitions1Σg-→ 1Πu and 1Σu+ → 1Πg.But this should be checked in further calculations which must include higher orbitals as basis functions.

The Importance of Photodissociative Trichloromethanol for Atmospheric Chemistry

2003 ◽  
Vol 68 (12) ◽  
pp. 2297-2308 ◽  
Author(s):  
Max Mühlhäuser ◽  
Melanie Schnell ◽  
Sigrid D. Peyerimhoff
Keyword(s):  
Energy Range ◽  
Excited States ◽  
Atmospheric Chemistry ◽  
Configuration Interaction ◽  
Configuration Interaction Calculations

Multireference configuration interaction calculations are carried out for ground and excited states of trichloromethanol to investigate two important photofragmentation processes relevant to atmospheric chemistry. For CCl3OH five low-lying excited states in the energy range between 6.1 and 7.1 eV are found to be highly repulsive for C-Cl elongation leading to Cl2COH (X2A') and Cl (X2P). Photodissociation along C-O cleavage resulting in Cl3C (X2A') and OH (X2Π) has to overcome a barrier of about 0.8 eV (13A'', 11A'') and 1.2 eV (13A') because the low-lying excited states 11A'', 13A' and 13A'' become repulsive only after elongating the C-O bond by about 0.3 Å.

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