Disorder and the extent of polymerization in calcium silicate and aluminosilicate glasses: O-17 NMR results and quantum chemical molecular orbital calculations

2006 ◽  
Vol 70 (16) ◽  
pp. 4275-4286 ◽  
Author(s):  
Sung Keun Lee ◽  
Jonathan F. Stebbins
Keyword(s):  
Molecular Orbital ◽  
Calcium Silicate ◽  
Quantum Chemical ◽  
Molecular Orbital Calculations ◽  
Aluminosilicate Glasses

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

A pairwise additivity scheme for conformational energies of substituted ethanes

1975 ◽  
Vol 343 (1632) ◽  
pp. 1-10 ◽  
Keyword(s):  
Large Deviations ◽  
Ab Initio ◽  
Dihedral Angle ◽  
Molecular Orbital ◽  
Methyl Groups ◽  
Molecular Orbital Calculations ◽  
Linear Combinations ◽  
Strongly Interacting ◽  
Conformational Energies

Ab initio molecular orbital calculations are used to explore additivity in the conformational energies of poly-substituted ethanes in terms of conformational energies of ethane and appropriate mono- and 1,2-di-substituted derivatives. Such relations would allow complex calculations for poly-substituted ethanes to be replaced by much simpler ones on a small number of parent molecules. General expressions for the linear combinations are derived from the assumption that interactions between vicinal substituents are pairwise additive and depend only on the vicinal dihedral angle. The additivity scheme is tested for 15 ethanes, di-, tri- or tetrasubstituted by cyano and methyl groups and for a smaller number of fluoroethanes. Additivity applies to within 0.1- 0.3 k J mol -1 in the methylethanes and mostly to within about 0.7- 0.8 kJ mol -1 in cyanoethanes. Large deviations are found among the geminally substituted fluoroethanes. It is suggested that the additivity approximation is most successful in the absence of strongly interacting geminal groups. Predictions are made of conformational energies of ten hexa(cyano- and methyl-) substituted ethanes.

ChemInform Abstract: MOLECULAR ORBITAL CALCULATIONS ON THE C2H4SH+ CATION

1976 ◽  
Vol 7 (10) ◽  
pp. no-no
Author(s):  
JAMES W. GORDON ◽  
GEORGE H. SCHMID ◽  
IMRE G. CSIZMADIA
Keyword(s):  
Molecular Orbital ◽  
Molecular Orbital Calculations
Sign in / Sign up

Export Citation Format

Share Document