TITLE

Ab Initio and density functional theory study of the interaction in formamide and thioformamide dimers and trimers

AUTHOR(S)
Cabaleiro-Lago, Enrique M.; Otero, Jesu´s Rodrı´guez
PUB. DATE
July 2002
SOURCE
Journal of Chemical Physics;7/22/2002, Vol. 117 Issue 4, p1621
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
In this work, clusters consisting of two and three formamide or thioformamide molecules were subjected to ab initio and density functional theory calculations using the aug-cc-pvdz/cc-pvdz basis set. Formamide and thioformamide dimers were both found to exhibit five different minima on their potential surfaces involving hydrogen bonds of the N-H···X=C or C-H···X=C (X=O, S) type. The most stable structure in both cases is a cyclic configuration of Csub 2h] symmetry involving two identical N-H···X=C bonds. The interaction energy for such a structure is -60 and -48 kJ/mol for formamide and thioformamide, respectively. Based on the calculations, each N-H···X=C bond contributes - 30 kJ/mol to it in formamide and - 24 kJ/mol in thioformamide. On the other hand, each N-H···X=C bond contributes -9.7kJ/mol in formamide and -ll.7kJ/mol in thioformamide. The interaction causes appreciable distortion in the molecules, particularly in the N-H groups involved in a hydrogen bond, which are lengthened by up to 0.019 and 0.013 Å in formamide and thioformamide, respectively. The trimer structures identified on the potential surfaces of formamide and thioformamide are cyclic configurations capable of establishing 3 or 4 hydrogen bonds. While formamide tends to adopt planar configurations (the most stable of which possesses an interaction energy of -105 kJ/mol), thioformamide forms preferentially nonplanar structures (the most stable being a nonplanar cyclic configuration with an interaction energy of - 88 kJ/mol). The contribution of nonadditive pairwise terms is not particularly significant in either compound, which suggests the absence of substantial cooperative phenomena in the trimers. However, this contribution is crucial with a view to determining the stability sequence for the trimers, where the most stable structures result from the contribution of nonadditive...
ACCESSION #
6959726

 

Related Articles

  • Microwave spectrum and structural parameters for the formamide-formic acid dimer. Daly, Adam M.; Sargus, Bryan A.; Kukolich, Stephen G. // Journal of Chemical Physics;11/7/2010, Vol. 133 Issue 17, p174304 

    The rotational spectra for six isotopologues of the complex formed between formamide and formic acid have been measured using a pulsed-beam Fourier transform microwave spectrometer and analyzed to obtain rotational constants and quadrupole coupling parameters. The rotational constants and...

  • An investigation of density functionals: The first-row transition metal dimer calculations. Yanagisawa, Susumu; Tsuneda, Takao; Hirao, Kimihiko // Journal of Chemical Physics;1/8/2000, Vol. 112 Issue 2 

    The performance of different density functional theory (DFT) methods was investigated in the calculations of the bond length and the binding energy of the first-low transition metal dimers. The 4s-3d interconfigurational energies and 4s and 3d ionization potentials were also calculated for the...

  • Chemisorption of NH[sub 3] on Si(100)-(2x1): A study by first-principles ab initio and density functional theory. Loh, Zhi-Heng; Zhi-Heng Loh; Kang, H. Chuan // Journal of Chemical Physics;2/1/2000, Vol. 112 Issue 5 

    The energetics involved in the chemisorption of NH[sub 3] on Si(100)-(2x1) have been examined using ab initio and nonlocal density functional theory. One- and two-dimer cluster models were employed to model the Si(100)-(2x1) surface. By using various exchange-correlation functionals and Gaussian...

  • Very strong hydrogen bonds in neutral molecules: The phosphinic acid dimers. Gonzalez, Leticia; Mo, Otilia // Journal of Chemical Physics;8/15/1998, Vol. 109 Issue 7, p2685 

    Examines the use of ab initio orbital and density functional for the study of the structures and binding energies of the phosphinic acid (PA) dimers. Discussion of the stable dimers of PA; Evaluation of the structure, harmonic vibrational frequencies and bonding of the stable dimer of the...

  • Geometry of dimer reconstruction on the C(100), Si(100), and Ge(100) surfaces. Yang, C.; Kang, H. Chuan // Journal of Chemical Physics;6/8/1999, Vol. 110 Issue 22, p11029 

    Studies the geometry of dimer reconstruction on the carbon, silicon and germanium surfaces by density-functional calculations. Resolving differences in results from slab and cluster calculations; Symmetric dimmer geometry for carbon surface and an asymmetric dimmer geometry for the silicon and...

  • Theoretical study of the mechanism of recombinative hydrogen desorption from the monohydride phase of Si(100): The role of defect migration. Nachtigall, P.; Jordan, K. D.; Sosa, Carlos // Journal of Chemical Physics;11/1/1994, Vol. 101 Issue 9, p8073 

    Density functional theory with nonlocal corrections is used together with cluster models to examine various pathways for H2 desorption from the Si(100)2×1 surface. The barrier calculated for direct desorption of H2 from the doubly-occupied dimer is appreciably larger than the experimentally...

  • Helium dimer dispersion forces and correlation potentials in density functional theory. Allen, Mark J.; Tozer, David J. // Journal of Chemical Physics;12/22/2002, Vol. 117 Issue 24, p11113 

    The dispersion interaction in the helium dimer is considered from the viewpoint of the force on a nucleus. At large internuclear separations, Brueckner coupled cluster BD(T) forces agree well with near-exact dispersion forces. The atomic density distortion associated with the dispersion force is...

  • Density functional study of the NO dimer using GGA and LAP functionals. Duarte, H.A.; Proynov, E. // Journal of Chemical Physics;7/1/1998, Vol. 109 Issue 1, p26 

    Presents a density functional study of the NO dimer using the generalized gradient approximation (GGA) and LAP functionals. Implications of the ON-NO bonding in the NO dimer for theoretical and experimental methods; Impact of the LAP exchange-correlation schemes on the results; Exploration of...

  • Strong coupling of the single excitations in the Q-like bands of phenylene-linked free-base and zinc bacteriochlorin dimers: A time-dependent density functional theory study. Yamaguchi, Yoichi; Yokoyama, Shiyoshi; Mashiko, Shinro // Journal of Chemical Physics;4/15/2002, Vol. 116 Issue 15, p6541 

    Time-dependent density-functional theory (TDDFT) calculations were carried out to predict the Q-like bands of the two structural isomers of the phenylene-linked free-base (FBBC) and zinc (ZnBC) bacteriochlorin dimers. The calculated singlet excitation energies and oscillator strengths for the...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics