نتایج جستجو برای: semiempirical quantum mechanics

تعداد نتایج: 337980  

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2001
parviz rashidi ranjbar ali mohajeri mehran ghiaci

the ability of the present semiempirical quantum mechanics methods are surveyed for reproducing the transannular interaction in the bifunctional n-phenyl-5-azocanones. the am1 method is the best with the order of reliability being am1, pm3, mndo and mindo/3. am1 calculations were then carried out for quantification of transannular interaction. the n(o) ionization potential has been used for thi...

1998
Thomas R. Cundari Leah Saunders Laura L. Sisterhen

A force field for vanadium-oxos was developed and tested with a variety of complexes with coordination numbers of 5 or 6 and formal oxidations states of +4 or +5 on the metal. Similarly, a semiempirical quantum mechanical method for transition metals was extended to vanadium. In this research soft and hard ligands were studied, as were ligands coordinated through single, multiple, and dative bo...

Ali Mohajeri Mehran Ghiaci Parviz Rashidi Ranjbar,

The ability of the present semiempirical quantum mechanics methods are surveyed for reproducing the transannular interaction in the bifunctional N-phenyl-5-azocanones. The AM1 method is the best with the order of reliability being Am1, PM3, MNDO and MINDO/3. AM1 calculations were then carried out for quantification of transannular interaction. The n(o) ionization potential has be...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1996
P A Bash L L Ho A D MacKerell D Levine P Hallstrom

We describe a procedure for the generation of chemically accurate computer-simulation models to study chemical reactions in the condensed phase. The process involves (i) the use of a coupled semiempirical quantum and classical molecular mechanics method to represent solutes and solvent, respectively; (ii) the optimization of semiempirical quantum mechanics (QM) parameters to produce a computati...

Journal: :حکمت و فلسفه 0
علی پایا هیئت علمی دانشگاه علامه طباطبایی

the aim of the present paper is to sbo» that anti-realism in science, 1vhich has a1;guab/y become more fashionable in recentyears, contrary to tuha: its proponents assert, cannot make use of quantum mechanics and its impressiue achievements as a frump card in justifying its claims. i will argue that scientific anti-realism far from providing scientific communiry with a progressive methodologica...

2001
Andrey A. Bliznyuk Alistair P. Rendell Toby W. Allen Shin-Ho Chung

The molecular electrostatic potential inside the potassium channel protein from Streptomyces liVidans has been investigated using linear scaling semiempirical quantum chemical method, for a variety of geometries, with and without solvating water molecules. The results are compared with those given by a number of popular molecular mechanics force-fields. The difference between the quantum and mo...

Journal: :BMC Chemical Biology 2001
Ami Lakdawala Minmin Wang Neysa Nevins Dennis C Liotta Danuta Rusinska-Roszak Marek Lozynski James P Snyder

BACKGROUND: Molecular mechanics (MM) and quantum chemical (QM) calculations are widely applied and powerful tools for the stereochemical and conformational investigations of molecules. The same methods have been extensively used to probe the conformational profile of Taxol (Figure 1) both in solution and at the beta-tubulin protein binding site. RESULTS: In the present work, the relative energi...

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 1989
S N Bushelev N F Stepanor

Semiempirical CNDO/2 calculations of the electronic and molecular structures have been carried out for six antitumor anthracycline antibiotics. The strong correlation between their biological activity and such molecular properties as chromophore dipole moment, energy of frontier orbitals, and steric volumes was found and the proper QSAR equations were constructed. The molecular mechanics model ...

Journal: :international journal of advanced biological and biomedical research 2013
fahimeh shojaie

there are many claims that quantum mechanics plays a key role in the origin and/or operation of biological organisms. the mechanism of the meiosis, mitosis and gametes life cycle from the view-point of quantum for human has been represented. the quantum gates have been used to simulate these processes for the first time. the reason of several hundred sperms has been explained in the male too

براتی, محمدحسین, مشهدی, میثم , کاظمی, محمدجواد,

 In this article, a causal model on the basis of trajectory is introduced for description of quantum systems. This theory is structurally very similar to Bohme mechanics, and like Bohme theory reproduces all statistical consequences of standard quantum mechanics. Particle trajectories in this model are different from anticipated ones by Bohme model. Quantum potential (force) form, which is give...

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