نتایج جستجو برای: pm3
تعداد نتایج: 474 فیلتر نتایج به سال:
Adiabatic ionization energy (AIE) calculations were performed at the AM1, PM3, PM6, PDDG, HF/QZVP, and B3LYP/QZVP levels of theory on 722 atmospherically relevant organic compounds with available experimental kOH . From the starting set of molecules, a final suite of 114 monoand polyfunctionalized compounds provided converged neutral and cationic geometries without imaginary frequencies for all...
Semiempirical molecular orbital calculations have been performed for the first step in the alkaline hydrolysis of the neutral benzoylester of cocaine. Successes, failures, and limitations of these calculations are reviewed. A PM3 calculated transition state structure is compared with the PM3 calculated structure for the hapten used to induce catalytic antibodies for the hydrolysis of cocaine. I...
طیف سنجی رزونانس چهارقطبی هسته یکی از مفیدترین روشها در تعیین توزیع الکترونی و شناسایی ترکیبات شیمیایی میباشد. در این پروژه جمعیت الکترونی اربیتالهای py و pz اتم ید در تعدادی از ترکیبات آلی و معدنی یددار با استفاده از معادلات و مقادیر تجربی فرکانس nqr و پارامتر ضدتقارن بدست آمده است و با جمعیت الکترونی اربیتالهای py و pz محاسبه شده به روش pm3 مقایسه شده است . همچنین پارامترهای nqr هسته ید (i 5/...
Two new semiempirical methods employing a Pairwise Distance Directed Gaussian modification have been developed: PDDG/PM3 and PDDG/MNDO; they are easily implemented in existing software, and yield heats of formation for compounds containing C, H, N, and O atoms with significantly improved accuracy over the standard NDDO schemes, PM5, PM3, AM1, and MNDO. The PDDG/PM3 results for heats of formatio...
In cereals, several mildew resistance genes occur as large allelic series; for example, in wheat (Triticum aestivum and Triticum turgidum), 17 functional Pm3 alleles confer agronomically important race-specific resistance to powdery mildew (Blumeria graminis). The molecular basis of race specificity has been characterized in wheat, but little is known about the corresponding avirulence genes in...
Meloidogyne incognita root-knot nematode is one of the main causes tomato root damage and consequently crop production losses. Thus, in vitro conditions, number nematodes hatched eggs (%) at 4 6 days mortality (J2 stage) 8, 18, 24 h, were evaluated Petri dishes containing candidate rhizobacteria Enterobacter asburiae (BA4-19 PM3-14), Acinetobacter calcoaceticus (BM2-12), Klebsiella variicola (B...
The results of MNDO, AM1 and PM3 semi-empirical calculations and HF/6-31G*, MP/6-31G*, MP2/6-311+G**, and B3LYP/6-311G** and QCISD/6-31G* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (Z,Z,Z)-cycloocta-1,3,5-triene indicate that all methods, except PM3, predict wrong ordering of the conformations.
The Sparkle/PM3 model is extended to cerium(III) complexes. The validation procedure was carried out using only high quality crystallographic structures (R factor < 0.05Å), for a total of thirty-seven Ce(III) complexes. The Sparkle/PM3 unsigned mean error, for all interatomic distances between the Ce(III) ion and the directly coordinating oxygen or nitrogen atoms, is 0.080Å, a level of accuracy...
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