Semi-empirical MO-CI calculations on excited states

1971 ◽  
Vol 22 (4) ◽  
pp. 325-329 ◽  
Author(s):  
D. R. Salahub
Keyword(s):  
Excited States ◽  
Semi Empirical ◽  
Ci Calculations

Excited states of all-trans and 11-cis retinal: All valence-electron SCF-MO-CI calculations

2009 ◽  
Vol 9 (S2) ◽  
pp. 9-24
Author(s):  
Ludwik J. Weimann ◽  
Gerald M. Maggiora ◽  
Paul E. Blatz
Keyword(s):  
Excited States ◽  
Valence Electron ◽  
Ci Calculations

MRD CI calculations on the asymmetric stretch potentials of H2O in the ground and the first seven singlet excited states

1985 ◽  
Vol 96 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Giannoula Theodorakopoulos ◽  
Ioannis D. Petsalakis ◽  
Robert J. Buenker
Keyword(s):  
Excited States ◽  
Asymmetric Stretch ◽  
Ci Calculations

Angeregte Zustände des Fluormoleküls

1974 ◽  
Vol 29 (10) ◽  
pp. 1425-1430 ◽  
Author(s):  
E. Kasseckert ◽  
B. Wirsam
Keyword(s):  
Excited States ◽  
Band System ◽  
Stable States ◽  
Ci Calculations ◽  
Potential Curves

Abstract For the lower lying excited states of the fluorine molecule elaborated SCF-CI calculations have been carried out. The discussion of the potential curves of some higher excited stable states leads to the conclusion that the experimentally observed orange band-system may belong to two transitions 1Σg+ - 1Πu and 1Σu- - 1Πg .

Some semi-empirical molecular orbital studies of the origin of conformational preferences for free S2O42- and N2O4

1984 ◽  
Vol 37 (7) ◽  
pp. 1553 ◽  
Author(s):  
RD Harcourt ◽  
BJ Smith ◽  
CJ Marsden
Keyword(s):  
Molecular Orbital ◽  
Rotation Barrier ◽  
Coulombic Repulsion ◽  
Barrier Analysis ◽  
Trans Conformer ◽  
Conformational Preferences ◽  
Semi Empirical ◽  
Ci Calculations

The results of some semi-empirical MO-CI calculations of the barriers to rotation around the S-S and N-N bonds of S2O42- and N2O4 are reported. The calculated barriers are expressed in terms of atomic, cis O-O overlap, coulombic repulsion and exchange contributions. The barrier analysis for N2O4 shows that cis O-O overlap stabilizes the planar relative to the skew conformer, whereas for free S2O42-, reduced coulombic repulsions stabilize the trans conformer relative to the eclipsed. Some CNDO/2 estimates of the rotation barrier for S2O42- are also reported.

Polar substituents in barrelene photochemistry: mechanistic aspects of the photochemistry of 2-cyanobenzobarrelene

1978 ◽  
Vol 56 (23) ◽  
pp. 3027-3037 ◽  
Author(s):  
Christopher Owen Bender ◽  
Dee W. Brooks ◽  
William Cheng ◽  
Douglas Dolman ◽  
Seamus F. O'Shea ◽  
...  
Keyword(s):  
Excited States ◽  
Interaction Energies ◽  
Direct Photolysis ◽  
Deuterium Labelling ◽  
Atom Interaction ◽  
Polar Substituents ◽  
Triplet Excited States ◽  
Ci Calculations

The direct photolysis of 2-cyanobenzobarrelene (4) yields 5- and 7-cyanobenzocyclooctatetraene [Formula: see text] and 1-cyanobenzosemibullvalene [Formula: see text], whereas the acetophenone sensitized irradiation of 4 yields only 8 [Formula: see text]. Deuterium labelling studies suggest that 7 derives from an initial 2Π + 2Π cycloaddition between the vinyl and vinylcyano bridges of 4, whereas 8, resulting from direct or sensitized irradiations of 4, derives from di-Π-methane rearrangement involving initial vinyl–vinylcyano bridging. The observed initial bonding preferences of the 2Π + 2Π cycloadditions and di-Π-methane rearrangement of 4 are in accord with predictions based upon CNDO-CI calculations of changes in atom–atom interaction energies between possible bridging sites in singlet and triplet excited states of 4.

Excited states of four hemes in a c-type cytochrome subunit of the photosynthetic reaction center of Rhodopseudomonas viridis: SAC-CI calculations

2001 ◽  
Vol 05 (03) ◽  
pp. 256-266 ◽  
Author(s):  
K. OHKAWA ◽  
M. HADA ◽  
H. NAKATSUJI
Keyword(s):  
Reaction Center ◽  
Excited States ◽  
Photosynthetic Reaction Center ◽  
Linear Dichroism ◽  
The Other ◽  
Oscillator Strengths ◽  
Energy Separation ◽  
Ligand Effect ◽  
Ci Calculations ◽  
Homo Lumo

The excited states of four hemes, c-552, c-554, c-556, and c-559, in a c-type cytochrome subunit of the photosynthetic reaction center (PSRC) of Rhodopseudomonas (Rps.) viridis were studied using the symmetry-adapted cluster (SAC)-configuration interaction (CI) method. c-552 has two imidazole ligands, while the other three hemes have imidazole and methionine ligands. The electronic states of these four hemes are affected significantly by both the ligands and protein and water environments. The ligand effect classifies the four hemes into two groups, while the environmental effect is unique in each heme. The HOMO–LUMO energy separation of c-552 is much smaller than those of the other hemes, and therefore, the low-lying excited states of c-552 are more stable than those of the other hemes. The low-lying excited states and their oscillator strengths of c-559 are significantly modified by the environment when compared with c-556 and c-554. Some observed UV peaks of the PSRC of Rps. viridis were found to have been assigned reasonably to the excited states of these four hemes in a previous report. The calculated linear dichroism angles also supported our assignment.

scholarly journals Ab Initio Analysis of Exchange Interactions in [V2O(BIPY)4CL2]2+ Complex

2008 ◽  
Vol 3 (1) ◽  
pp. 112-117
Author(s):  
Ivan Ogurtsov ◽  
Andrei Tihonovschi
Keyword(s):  
Ab Initio ◽  
Excited States ◽  
Ground State ◽  
Exchange Interactions ◽  
Boltzmann Distribution ◽  
Molecular Orbitals ◽  
Vanadium Complex ◽  
Ferromagnetic Interaction ◽  
Ci Calculations ◽  
D Orbitals

In this work an ab initio analysis of the binuclear vanadium complex [V2O(bipy)4Cl2]2+ electronic structure is performed. The ground state was calculated to be a quintet, which means a ferromagnetic interaction between centers. The orbitals participating in exchange interaction according to ROHF+CI calculations are two molecular orbitals consisting of vanadium d-orbitals and two molecular orbitals with main contributions from p-orbitals of bipyridine ligands perpendicular to V-V axis, vanadium d- and p-orbitals and μ-oxygen p-orbital. Calculated energy values of the multielectronic states are placed in accordance with Lande rule. The value of magnetic moment at 293K calculated for the complex in vacuum taking into consideration the Boltzmann distribution and the energies of the excited states is 3.95BM which is in accordance with experimental value of 3.99BM (for complex in acetone).

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