AIM study on the transferability of the oxygen atom in linear ethers

2000 ◽  
Vol 78 (12) ◽  
pp. 1535-1543 ◽  
Author(s):  
Antonio Vila ◽  
Enrique Carballo ◽  
Ricardo A Mosquera

The integrated values of the electron population, electron energy, nucleus–electron potential energy interaction, dipole moment and volume of the oxygen atoms, and the main properties of the O—C bond critical points, were determined by employing the theory of atoms in molecules and 6-31++G**//6-31G* wave functions for a series of 25 unbranched alkyl monoethers. These results were used to assess the degree of approximate transferability of the oxygen atom along this series in terms of the particular alkyl radicals bonded to it. It has been found that a set of six different oxygen atoms is necessary to classify all the computed values. It can be established that the oxygen atoms bonded to propyl and larger radicals can be treated, in practice, as a transferable fragment, while those bonded to at least one smaller radical are specific. Though the total HF energy and the available experimental heats of formation are well fitted by a traditional additivity scheme that distinguishes only among O, CH2, and CH3 units, it has been found that the energy properties are influenced by the size of the molecule.Key words: transferability, AIM theory, ethers.

1980 ◽  
Vol 35 (10) ◽  
pp. 1066-1070 ◽  
Author(s):  
P. Rosmus ◽  
E.-A. Reinsch

Abstract Potential energy and dipole moment functions have been calculated for the ground states of the NeH+ (1.0 ≦ R ≦ 15 a. u.) and the KrH+ (1.6 ≦ R ≦ 20 a. u.) ion from highly correlated SCEP/VAR and SCEP/CEPA electronic wave functions. The following spectroscopic constants have been derived: Ne20H+ re = 0.996 ± 0.003 Å, ωe = 2896 ± 20cm-1 , D0(Ne + H+) = 2.10 ± 0.05 eV; Kr84H+ re = 1.419 ± 0.003 Å, ωe = 2561 ±20 cm-1 , D0(Kr + H+) = 4.65 ±0.05 eV. The Einstein transition probability coefficients of spontaneous emission have been calculated for all transitions v ≦ 5 of Ne20H+, Ne20D+, Kr84H+ and Kr84D+, respectively.


Author(s):  
Leila G. Ranis ◽  
Jacqueline Gianino ◽  
Justin M. Hoffman ◽  
Seth N. Brown

Eight-coordinate MoO2(DOPOQ)2 can donate two oxygen atoms to substrates such as phosphines in a four-electron nonclassical oxygen atom transfer reaction.


Author(s):  
Danillo Valverde ◽  
Sebastian Mai ◽  
Adalberto Vasconcelos Sanches de Araujo ◽  
Sylvio Canuto ◽  
Leticia Gonzalez ◽  
...  

The population and depopulation mechanisms leading to the lowest-lying triplet states of the 2-Se-Thymine were studied at the MS-CASPT2/cc-pVDZ level of theory. Several critical points on different potential energy hypersurfaces...


2018 ◽  
Author(s):  
Marc E. Segovia ◽  
Oscar Ventura

<p>Diffusion Monte Carlo (DMC) and Reptation Monte Carlo (RMC) methods, have been applied to study some properties of the NaK molecule. Hartree-Fock (HF), Density Functional (DFT) and single and double configuration interaction (SDCI) wavefunctions with a valence quadruple zeta atomic natural orbital (VQZ/ANO) basis set were used as trial wavefunctions. Values for the potential energy curve, dissociation energy and dipole moment were calculated for all methods and compared with experimental results and previous theoretical derivations. Quantum Monte Carlo (QMC) calculations were shown to be useful methods to recover correlation in NaK, essential to obtain a reasonable description of the molecule. The equilibrium distance—interpolated from the potential energy curves—yield a value of 3.5 Å, in agreement with the experimental value. The dissociation energy, however, is not as good. In this case, a conventional CCSD(T) calculation with an extended aug-pc-4 basis set gives a much better agreement to experiment. On the contrary, the CCSD(T), other MO and DFT methods are not able to reproduce correctly the large dipole moment of this molecule. Even DMC methods with a simple HF trial wavefunction are able to give a better agreement to experiment. RMC methods are even better, and the value obtained with a B3LYP trial wavefunction is very close to the experimental one.</p>


2006 ◽  
Vol 124 (6) ◽  
pp. 064311 ◽  
Author(s):  
Chikako Oyanagi ◽  
Kiyoshi Yagi ◽  
Tetsuya Taketsugu ◽  
Kimihiko Hirao

2018 ◽  
Vol 212 ◽  
pp. 33-49 ◽  
Author(s):  
Chen Qu ◽  
Joel M. Bowman

Full-dimensional (24 modes) quantum calculation of the IR spectrum of (DCOOD)2, and comparison with classical MD one.


1983 ◽  
Vol 38 (9) ◽  
pp. 1042-1043
Author(s):  
H. Lumbroso ◽  
E. Montoneri ◽  
G. C. Pappalardo

Abstract Analysis of the dipole moment of 2-chloropyridine-5-sulphonyl chloride in benzene at 30 °C (2.00 D) supports a model in which the C(5)-SCl group is rotated by 40° from the 2-chloro-1-pyridyl group (see Figure 1). Such a model, with the S-Cl chlorine atom close to the 1-azani-trogen atom, may be explained by interplay of two con-flicting factors, namely sulphonylchloride-arene conjuga-tion and lesser repulsion between one of the oxygen atoms and the aza-nitrogen atom.


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