scholarly journals Conformational study on the structures and energies of the weakly bound complexes of AlCl3 with diatomic molecules

2007 ◽  
Vol 5 (4) ◽  
pp. 1007-1018 ◽  
Author(s):  
Issac Jimenez-Fabian ◽  
Abraham Jalbout ◽  
Abderahim Boutalib
Keyword(s):  
Transition State ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Conformational Study ◽  
Weakly Bound ◽  
Hydrogen Halides ◽  
Strength Of Interaction ◽  
Weakly Bound Complexes ◽  
Aluminium Trichloride ◽  
High Level

AbstractIn this work we present the results of high level ab initio calculations on weakly bound complexes of aluminium trichloride and hydrogen halides, HX, halogens, X2 and diatomic interhalogens, XY (where X, Y = F, Cl, Br). Based upon these calculations we have predicted that all structures in the staggered conformation (except for Cl3AlFH and Cl3AlClH) are stable minima while those in the eclipsed configurations are transition state structures. In the XH complexes the strength of interaction with the Cl3Al group is FH > ClH > BrH. In the case of X2 species it is Br2 > F2 > Cl2, and finally in the XY (YX) group it is: FBr > ClBr > FCl > BrCl > BrF > ClF.

Configurational Assignment and Conformational Study of Methylglyoxal Bisdimethylhydrazones Derived from the 2-Ethoxypropenal Precursor

2006 ◽  
Vol 59 (3) ◽  
pp. 211 ◽  
Author(s):  
Leonid B. Krivdin ◽  
Lyudmila I. Larina ◽  
Kirill A. Chernyshev ◽  
Natalia A. Keiko
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Experimental Measurements ◽  
Conformational Study ◽  
Lone Pairs ◽  
Configurational Assignment ◽  
Out Of Plane ◽  
High Level

A configurational assignment of the isomeric methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor has been performed based on experimental measurements and high-level ab initio calculations of 1J(C,C) and 1J(C,H) couplings. The results reveal the marked stereochemical dependence upon the orientation of the lone pairs of both nitrogen atoms in different isomers. Methylglyoxal bisdimethylhydrazone is shown to exist in a mixture of the EE and ZE isomers (ca. 75:25), both of which adopt predominant s-trans conformations with minor (up to 8°) out-of-plane deviations.

scholarly journals Vibrational nonlinear optical properties of spatially confined weakly bound complexes

2017 ◽  
Vol 19 (35) ◽  
pp. 24276-24283 ◽  
Author(s):  
Robert Zaleśny ◽  
Marta Chołuj ◽  
Justyna Kozłowska ◽  
Wojciech Bartkowiak ◽  
Josep M. Luis
Keyword(s):  
Optical Properties ◽  
Ab Initio ◽  
Nonlinear Optical ◽  
Nonlinear Optical Properties ◽  
Weakly Bound ◽  
Spatial Confinement ◽  
Weakly Bound Complexes ◽  
High Level

Vibrational nonlinear optical properties of weakly bound complexes are less susceptible to spatial confinement than their electronic counterparts – a novel inference from high-levelab initiocomputations.

Nitro–Nitrite Isomerization and Transition State Switching in the Dissociation of Ionized Nitromethane: A Threshold Photoelectron–Photoion Coincidence Spectroscopy Study

2009 ◽  
Vol 15 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Brandon Ferrier ◽  
Anne-Marie Boulanger ◽  
David M.P. Holland ◽  
David A. Shaw ◽  
Paul M. Mayer
Keyword(s):  
Transition State ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Bond Cleavage ◽  
Cleavage Reaction ◽  
Nitrite Ion ◽  
Methyl Nitrite ◽  
Bond Cleavage Reaction ◽  
Entropy Of Activation ◽  
Lower Entropy

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been employed to investigate the competition between bond cleavage and rearrangement reactions in the dissociation of ionized nitromethane, 1. Modeling TPEPICO breakdown diagrams with a combination of RRKM theory and ab initio calculations at the G3 level of theory allowed the derivation of the activation energy for the isomerisation of 1 to ionized methyl nitrite, 2, 82 kJ mol−1. In addition, evidence was found for a transition state switch in the bond cleavage reaction in 1 leading to CH3• + NO2+. As internal energy increases, the effective transition state for this reaction becomes tighter (i.e. is characterized by a lower entropy of activation, Δ‡S). Fitted thresholds for NO+ and CH2OHO+ ions, originating from the isomeric methyl nitrite ion, are consistent with G3 level ab initio calculations.

Excitons in poly(para phenylene vinylene): a quantum-chemical perspective based on high-level ab initio calculations

2016 ◽  
Vol 18 (4) ◽  
pp. 2548-2563 ◽  
Author(s):  
Stefanie A. Mewes ◽  
Jan-Michael Mewes ◽  
Andreas Dreuw ◽  
Felix Plasser
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Phenylene Vinylene ◽  
High Level ◽  
Quantum Chemical Computations

Exciton analyses of high-level quantum-chemical computations for poly(paraphenylene vinylene) reveal the nature of the excitonic bands in PPV oligomers.

scholarly journals Exploration of the NH3–H2 van der Waals interaction by high level ab initio calculations

2008 ◽  
Vol 346 (1-3) ◽  
pp. 237-246 ◽  
Author(s):  
Mirjana Mladenović ◽  
Marius Lewerenz ◽  
Geraldine Cilpa ◽  
Pavel Rosmus ◽  
Gilberte Chambaud
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Van Der Waals ◽  
Van Der Waals Interaction ◽  
High Level

Regular polyhedral molecules. P20 and its inclusion compounds

1998 ◽  
Vol 76 (9) ◽  
pp. 1274-1279 ◽  
Author(s):  
Lubomír Rulísek ◽  
Zdenek Havlas ◽  
Stanislav Hermánek ◽  
Jaromír Plesek
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Inclusion Compounds ◽  
Vibrational Analysis ◽  
Kinetic Stability ◽  
Stabilizing Agents ◽  
Geometrical Properties ◽  
Regular Dodecahedron ◽  
Phosphorus Clusters ◽  
High Level

Based upon the geometrical properties of regular polyhedrons, the possibility of the existence of certain polyhedral molecules composed of only one element is investigated. A very promising candidate - the regular dodecahedron - is selected as the convenient polyhedral structural pattern and phosphorus as the appropriate element. A series of high-level ab initio calculations is performed on the dodecahedral P20 molecule, including predictions of its thermodynamic and kinetic stability, natural bond orbital analysis, vibrational analysis, and inclusion of some elements into the molecular skeleton. Due to the potential stabilizing agents that may eventually form stable inclusion compounds and the estimated high kinetic stability, the question of the possible existence of P20 is answered in the positive.Key words: ab initio calculations, inclusion compounds, P20, phosphorus clusters, polyhedra.

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