Comparison of the variational and bound perturbation theories in dipole polarizability calculations of molecular complexes

1998 ◽  
Vol 39 (3) ◽  
pp. 437-441
Author(s):  
Yu. F. Pedash ◽  
A. Yu. Semenov
2000 ◽  
Vol 98 (8) ◽  
pp. 481-491 ◽  
Author(s):  
George Maroulis, Constantinos Makris, Deme

2002 ◽  
Vol 4 ◽  
pp. 133-133
Author(s):  
D. Teyssier ◽  
P. Hennebelle ◽  
M. Pérault
Keyword(s):  

2020 ◽  
Author(s):  
Kaihua Zhang ◽  
Ty Balduf ◽  
Marco Caricato

<div> <div> <p> </p><div> <div> <div> <p>This work presents the first simulations of the full optical rotation (OR) tensor at coupled cluster with single and double excitations (CCSD) level in the modified velocity gauge (MVG) formalism. The CCSD-MVG OR tensor is origin independent, and each tensor element can in principle be related directly to experimental measurements on oriented systems. We compare the CCSD results with those from two density functionals, B3LYP and CAM-B3LYP, on a test set of 22 chiral molecules. The results show that the functionals consistently overestimate the CCSD results for the individual tensor components and for the trace (which is related to the isotropic OR), by 10-20% with CAM-B3LYP and 20-30% with B3LYP. The data show that the contribution of the electric dipole-magnetic dipole polarizability tensor to the OR tensor is on average twice as large as that of the electric dipole-electric quadrupole polarizability tensor. The difficult case of (1S,4S)-(–)-norbornenone also reveals that the evaluation of the former polarizability tensor is more sensitive than the latter. We attribute the better agreement of CAM-B3LYP with CCSD to the ability of this functional to better reproduce electron delocalization compared with B3LYP, consistently with previous reports on isotropic OR. The CCSD-MVG approach allows the computation of reference data of the full OR tensor, which may be used to test more computationally efficient approximate methods that can be employed to study realistic models of optically active materials. </p> </div> </div> </div> </div> </div>


Author(s):  
Narendar D ◽  
Ettireddy S

The content of this investigation was to study the influence of β-cyclodextrin and hydroxy propyl-β-cyclodextrin complexation on enhancement of solubility and dissolution rate of isradipine. Based on preliminary phase solubility studies, solid complexes prepared by freeze drying method in 1:1 molar ratio were selected and characterized by DSC for confirmation of complex formation. Prepared solid dispersions were evaluated for drug content, solubility and in vitro dissolution. The physical stability of optimized formulation was studied at refrigerated and room temperature for 2 months. Solid state characterization of optimized complex performed by DSC and XRD studies.  Dissolution rate of isradipine was increased compared with pure drug and more with HP-β-CD inclusion complex than β-CD. DSC and XRD analyzes that drug was in amorphous form, when the drug was incorporated as isradipine β-CD and HP-β-CD inclusion complex. Stability studies resulted in low or no variations in the percentage of complexation efficiency suggesting good stability of molecular complexes. The results conclusively demonstrated that the enhancement of solubility and dissolution rate of isradipine by drug-cyclodextrin complexation was achieved.   


2015 ◽  
Vol 12 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Leonid A. Yakovishin ◽  
Vladimir I. Grishkovets ◽  
Elena N. Korzh

2008 ◽  
Vol 73 (11) ◽  
pp. 1509-1524 ◽  
Author(s):  
Ivana Paidarová ◽  
Roman Čurík ◽  
Stephan P. A. Sauer

We illustrate for a set of small hydrocarbons, CH4, C2H4, C3H6 and C3H8, the important role of the electric dipole polarizability tensor and its geometric derivatives in theoretical models of electron energy-loss spectra (EELS). The coupled cluster linear response method together with Sadlej's polarized valence triple zeta basis set of atomic orbitals were used to calculate the polarizabilities and polarizability gradients. Incorporation of these ab initio data into the discrete momentum representation method (DMR) leads to perfect agreement between theory and collision experiments.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Z. Q. Wang ◽  
K. Nithyanandan ◽  
A. Coillet ◽  
P. Tchofo-Dinda ◽  
Ph. Grelu

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