Na+Binding to Cyclic and Linear Dipeptides. Bond Energies, Entropies of Na+Complexation, and Attachment Sites from the Dissociation of Na+-Bound Heterodimers and ab Initio Calculations

1998 ◽  
Vol 120 (10) ◽  
pp. 2437-2448 ◽  
Author(s):  
Blas A. Cerda ◽  
Sophie Hoyau ◽  
Gilles Ohanessian ◽  
Chrys Wesdemiotis
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Bond Energies ◽  
Attachment Sites

Generalized valence bond study of rotational singlet structures and pi bond energies for systems containing C==C, Si==Si, and C==Si double bonds

1998 ◽  
Vol 76 (4) ◽  
pp. 477-482 ◽  
Author(s):  
Youliang Wang ◽  
Raymond A Poirier
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Bond Energy ◽  
Valence Bond ◽  
Double Bonds ◽  
Bond Energies ◽  
Fluorine Substitution ◽  
Generalized Valence Bond ◽  
Pi Bonds ◽  
Optimized Geometries

Ab initio GVB(6/12)/6-31G** calculations were performed on A2X==YB2 (A, B = H, F; X, Y = C, Si) to obtain the optimized geometries for planar and twisted singlet structures, and to also calculate pi bond energies (rotational barriers). The nature of C-C, Si-Si, and C-Si pi bonds has been investigated. The results show that the C-C pi bond energy (E pi (ethene) = 65.4 kcal/mol) decreases with increasing fluorine substitution. The pyramidalization at the carbon or silicon center for the twisted structures decreases the pi bond energies in the substituted ethenes and their silicon counterparts. The Si-Si (E pi (disilene) = 23.2 kcal/mol) and C-Si (E pi (silaethene) = 31.6 kcal/mol) pi bonds become much weaker. Fluorine substitution stabilizes both the diradical and the dipolar twisted singlet structures.Key words: pi bond energy, ab initio calculations, generalized valence bond, fluorine substitution, disilene, and silaethene.

Millimetre-wave and infrared spectroscopy of Br13 CN: anharmonic force field of cyanogen bromide from spectroscopic data and ab initio calculations

1997 ◽  
Vol 90 (3) ◽  
pp. 495-497
Author(s):  
CLAUDIO ESPOSTI ◽  
FILIPPO TAMASSIA ◽  
CRISTINA PUZZARINI ◽  
RICCARDO TARRONI ◽  
ZDENEK ZELINGER
Keyword(s):  
Infrared Spectroscopy ◽  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Spectroscopic Data ◽  
Cyanogen Bromide ◽  
Millimetre Wave ◽  
Anharmonic Force

Ab Initio Calculations of Defects in CdMnSe Semimagnetic Semiconductors

2020 ◽  
Vol 55 (1) ◽  
pp. 108-113
Author(s):  
M. A. Mehrabova ◽  
H. S. Orujov ◽  
N. H. Hasanov ◽  
A. I. Kazimova ◽  
A. A. Abdullayeva
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Semimagnetic Semiconductors
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