نتایج جستجو برای: natural bond orbital population analysis

تعداد نتایج: 3797575  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان - دانشکده علوم پایه 1388

در این تحقیق روش های شیمی کوانتومی جهت ارزیابی برهمکنش ها ی مولکول های متفاوت از طریق بررسی انرژی پتانسیل سطح در راستای تعیین کارآیی بازدارندگی بعضی از مشتقات پیریدین در ممانعت از خوردگی آلومنیوم در محیط اسیدکلریدریک با استفاده از روش های "ab initio" و نیمه تجربی در مقایسه با داده های تجربی مورد استفاده قرارگرفته است. انرژی کل مولکول های ممانعت کننده وبالاترین سطح انرژی پرشده اوربیتال مولکولی م...

Journal: :The journal of physical chemistry. B 2006
Monika Sobczyk Jack Simons

Ab initio electronic structure methods are used to estimate the cross sections for electron transfer from donor anions having electron binding energies ranging from 0.001 to 0.6 eV to each of three sites in a model disulfide-linked molecular cation. The three sites are (1) the S-S sigma(*) orbital to which electron attachment is rendered exothermic by Coulomb stabilization from the nearby posit...

2010
Tu Anh Tran Carl H. Schiesser

Ab initio and DFT molecular orbital calculations predict that acetyl radical reacts with acetylene through interactions primarily involving the SOMO of the radical and the in-plane π-bond of acetylene. An energy barrier (∆E1) of 39.6 kJ mol‒1 is predicted for the preferred anti arrangement of reactants at the CCSD(T)/cc-pVDZ//BHandHLYP/cc-pVDZ level of theory. NBO analysis reveals additional in...

Journal: :Dalton transactions 2014
Miguel A del Águila-Sánchez Neidemar M Santos-Bastos Maria C Ramalho-Freitas Jesús García López Marcos Costa de Souza Jackson A L Camargos-Resende María Casimiro Gilberto Alves-Romeiro María José Iglesias Fernando López Ortiz

ortho Substituted (diphenylphosphoryl)-, (diphenylphosphorothioyl)- and (diphenylphosphoroselenoyl)-phosphinic amides o-C6H4(P(X)Ph2)(P(O)N(i)Pr2) (X = O (20a), S (20b), Se (20c)) were synthesized by ortho directed lithiation of N,N-diisopropyl-P,P-diphenylphosphinic amide (Ph2P(O)N(i)Pr2) followed by trapping with Ph2PCl and subsequent oxidation of the o-(diphenylphosphine)phosphinic amide (19...

Journal: :Physical chemistry chemical physics : PCCP 2009
Tomasz Ratajczyk Slawomir Szymanski

In three 9-silyltriptycenes bearing chlorine, bromine and the methyl group in one of the peri positions, the silyl group suffers extreme hindrance of its reorientational motion. Owing to this, separate signals of the individual silyl group protons could be observed in NMR spectra at relatively high temperatures. For each compound, the measured values of J couplings of these protons to the 29Si ...

2013
M. Oftadeh N. Madadi Mahani M. Hamadanian

Accurate quantum chemical computations based on density functional theory (DFT) were performed on the series of 2-(4-(naphthalen-2-yl)-1,2,3-thiadiazol-5-ylthio)-N-acetamide (TTA) derivatives. The local reactivity of the acetamide derivatives as anti-HIV drugs were studied in terms of Fukui functions in the framework of DFT. The results based on the basis set superposition error (BSSE) correcti...

2017
Nguyen Xuan Truong Bertram Klaus August Jaeger Sandy Gewinner Wieland Schöllkopf Otto Dopfer

Binary nanoclusters are of great interest for understanding fundamental phenomena related to applied materials science. Herein, neutral silicon-rich silicon−boron clusters (SinBm, n = 3−8, m = 1−2) are characterized by means of resonant infrared-ultraviolet two-color ionization (IR-UV2CI) spectroscopy, mass spectrometry, and quantum chemical calculations. Global energy optimizations are employe...

Journal: :Journal of Computational Chemistry 2001
Christopher J. Cramer Anne-Marie Kelterer Alfred D. French

Rotational coordinates about the C(3)–O(4) bonds of 2,4-dioxaheptane (DOH) and 2,4,6-trioxaheptane (TOH) are compared at correlated levels of electronic structure theory for gauche and trans orientations of the O(2)–C(3) bonds. TOH has overlapping anomeric effects, while DOH does not. The overlapping stereoelectronic effect shows its largest impact on the length of the O(2)–C(3) bond, which is ...

2005
Ju-Guang Han Jorge A. Morales

The first systematic study of the CrðH2OÞ n ðnZ1K4Þ series of clusters is herein presented at the level of the unrestricted DFT B3LYP level in conjunction with electron core potential basis sets. The present structures are relevant for laser-induced and laser-ablation syntheses of chromium compounds, and also for fundamental spectroscopy studies of metal-bearing species in the gas phase. Calcul...

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