A unified approach to the determination of infrared and Raman vibrational optical activity intensities using localized molecular orbitals

1981 ◽  
Vol 75 (10) ◽  
pp. 4847-4851 ◽  
Author(s):  
Laurence A. Nafie ◽  
Teresa B. Freedman
Keyword(s):  
Optical Activity ◽  
Molecular Orbitals ◽  
Unified Approach ◽  
Localized Molecular Orbitals

scholarly journals Localized molecular orbitals for calculation and analysis of vibrational Raman optical activity

2018 ◽  
Vol 20 (45) ◽  
pp. 28751-28758 ◽  
Author(s):  
Sandra Luber
Keyword(s):  
Optical Activity ◽  
Molecular Orbitals ◽  
Localized Molecular Orbitals ◽  
Raman Optical Activity ◽  
Chiral Systems ◽  
Spectroscopic Signatures ◽  
Insight Into ◽  
The Way

First calculations of vibrational Raman optical activity based on localized molecular orbitals are presented, which pave the way for novel insight into spectroscopic signatures of chiral systems.

scholarly journals Extracting Extremely Localized Molecular Orbitals from X-ray Diffraction Data

2014 ◽  
Vol 70 (a1) ◽  
pp. C284-C284 ◽  
Author(s):  
Alessandro Genoni
Keyword(s):  
Wave Function ◽  
Diffraction Data ◽  
Accurate Determination ◽  
Molecular Orbitals ◽  
X Ray Diffraction ◽  
Electron Densities ◽  
X Ray ◽  
Localized Molecular Orbitals ◽  
Electron Distributions

The accurate determination of electron densities in crystals from high-resolution X-ray diffraction data has become more and more important over the years. The existing techniques to accomplish this task can be subdivided into two great families: the multipole models and the wave function-based strategies. The former, which are the most widely used, are essentially linear scaling and allow an easy chemical interpretation of the obtained molecular charge densities, but they are also characterized by some drawbacks, such as the possible presence of unphysical negative regions in the resulting electron distributions. On the contrary, the latter always provide quantum mechanically rigorous electron densities, but they are more computationally expensive and, above all, the ease of chemical interpretation is almost completely lost. In this context, in order to combine the easy chemical interpretability of the multipole models with the quantum mechanical rigor of the wave-function based methods, we have recently extended the X-ray constrained wave function approach proposed by Jayatilaka in the framework of a quantum chemistry technique for the a priori determination of Extremely Localized Molecular Orbitals (ELMOs), namely we have developed a new strategy that allows to extract from X-ray diffraction data a single Slater determinant built up wit Molecular Orbitals strictly localized on small molecular fragments (e.g., atoms, bonds or functional groups). Preliminary tests have shown that the determination of X-ray constrained ELMOs is really straightforward. Furthermore, given the reliable transferability of the obtained Molecular Orbitals, we are constructing new ELMOs databases that can be used as alternative to the existing pseudo-atoms libraries for refining crystallographic structures and electron distributions of large systems. A detailed comparison between the new technique and the multipole models is also currently under investigation.

Simple theoretical models for elimination reactions on polar catalysts; The reactivity of halogeno-, hydroxy-, amino- and mercaptopropane

1982 ◽  
Vol 47 (8) ◽  
pp. 2180-2189 ◽  
Author(s):  
Jiří Sedláček
Keyword(s):  
Theoretical Models ◽  
Molecular Orbitals ◽  
Localized Molecular Orbitals ◽  
Hydroxy Amino ◽  
Elimination Reactions ◽  
Simple Models

CNDO/2 calculations have been made for simple models of the adsorption of (CH3)2CHZ molecules (Z = Cl, OH, NH2, and SH) on the surface of polar catalysts. The results of these calculations and their interpretation by the method of configuration analysis in terms of uniformly localized molecular orbitals made it possible to explain satisfactorily a series of experimental facts. The mechanism and stereoselectivity of the reaction as well as reactivity trends for the series of the molecules studied are discussed.

Unitary Optimization of Localized Molecular Orbitals

2013 ◽  
Vol 9 (12) ◽  
pp. 5365-5372 ◽  
Author(s):  
Susi Lehtola ◽  
Hannes Jónsson
Keyword(s):  
Molecular Orbitals ◽  
Localized Molecular Orbitals
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