A correlation of the lowest Hueckel molecular orbital transition energies with the L(sub b) band frequencies of thiapyrylium ions

1967 ◽  
Vol 32 (2) ◽  
pp. 444-449 ◽  
Author(s):  
Thomas Edwin Young ◽  
Cyrus J. Ohnmacht
Keyword(s):  
Molecular Orbital ◽  
Transition Energies ◽  
Orbital Transition

Molecular Orbital Theory of the Electronic Structure of Organic Compounds

1981 ◽  
Vol 36 (5) ◽  
pp. 494-501
Author(s):  
Horacio Grinberg ◽  
Norma Sbarbati Nudelman ◽  
Julio Marañón ◽  
Oscar M. Sorarrain ◽  
Carlos F. Gómez
Keyword(s):  
Molecular Orbital ◽  
Excited States ◽  
Intramolecular Charge Transfer ◽  
Interaction Matrix ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Transition Energies ◽  
Experimental Values ◽  
Self Consistency ◽  
Good Interpretation

Abstract The semiempirical molecular orbital CNDO/S-CI spectral parameterization has been used to elucidate the lower electronic states of a series of dioxodiazacycloalkanes. The a1, b1, and a' occupied molecular orbitals lie predominantly on the oxygen, while a2, b2, and a" are largerly nonbonding orbitals delocalized on the nitrogen and oxygen atoms. The two lowest unoccupied virtual orbitals are predicted to be of b2, a2, and a" symmetry. These orbitals are strongly localized on the C = 0 group. The resulting 1 B2(u0π*) and 1 A2(n0π*) spectroscopic states involve intramolecular charge transfer from the oxygen to the carbon atom of the carbonyl group, which is supported by electron density calculations of these excited states. Although the calculated transition energies may not allow for absolute comparisons with experimental values, it appears that the introduction of self-consistency together with solvation energy and configuration interaction, when the elements of the interaction matrix are properly evaluated, lead to a fairly good interpretation of the singlet-singlet transitions. The lowest energy singlet excited state calculated for each structure is comprised almost entirely of the nπ* configuration.

A Semi-empirical Analysis of the Electronic Spectrum and Molecular Structure of Formaldehyde

1972 ◽  
Vol 50 (5) ◽  
pp. 646-652 ◽  
Author(s):  
I. Absar ◽  
C. S. Lin ◽  
K. L. McEwen
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Electronic Transitions ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Matrix Elements ◽  
Transition Energies ◽  
Relative Separation ◽  
Semi Empirical ◽  
Electronic Transition Energies

The electronic transition energies and ionization potentials of formaldehyde have been calculated by a semi-empirical molecular orbital method, using several different ways of evaluating the diagonal matrix elements, in an attempt to adapt the Pariser–Parr–Pople method to the calculation of σ electron properties. The use of theoretically computed penetration integrals in this semi-empirical calculation lead to incorrect relative separation of the π-, σ-, and nonbonding molecular orbital energies, and hence to failure in predicting n →π* and n → σ* transition energies. A method is developed which reproduces the spectrum of formaldehyde (which includes n–π*, π–π*, and n–σ* electronic transitions) satisfactorily. In paper II of this series, this method is applied to study the spectrum of HCN and CO2.

The relativistic coupled-cluster method: transition energies of bismuth and eka-bismuth

1998 ◽  
Vol 94 (1) ◽  
pp. 181-187 ◽  
Author(s):  
EPHRAIM ELIAV ◽  
UZI KALDOR ◽  
YASUYUKI ISHIKAWA
Keyword(s):  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Transition Energies

Interactions between Methylene Blue and Pullulan According to Molecular Orbital Calculations

2020 ◽  
Vol 140 (11) ◽  
pp. 529-533
Author(s):  
Pasika Temeepresertkij ◽  
Saranya Yenchit ◽  
Michio Iwaoka ◽  
Satoru Iwamori
Keyword(s):  
Methylene Blue ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations
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