Molecular orbital study of proton transfer in (H/sub 3/NHOH/sub 2/)/sup +/

Journal Article · Thu Mar 31 04:00:00 EST 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100230a010· OSTI ID:5654976

Scheiner, S ^[1]; Harding, L B

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1. Southern Illinois Univ., Carbondale

Ab initio molecular orbital methods are used to study transfer of the central proton in the asymmetric (H/sub 3/NHOH/sub 2/)/sup +/ system. Calculations are performed at the Hartree-Fock level with basis sets of split-valence (4-31G) and double-zeta plus polarization function (DZP) quality. The effects of electron correlation upon the transfer potentials are computed via the generalized valence bond (GVB) and polarization configuration interaction (POL-CI) techniques. The barrier to proton transfer between NH/sub 3/ and OH/sub 2/ is observed to heighten as the distance between the latter two molecules is increased. At the equilibrium R(NO) hydrogen-bond length, the transfer potential contains a single minimum, (H/sub 3/NH...OH/sub 2/)/sup +/, in which the central proton is more closely associated with NH/sub 3/. In both the rapid and adiabatic models of proton transfer, there is no energy barrier to decay of (H/sub 3/N...HOH/sub 2/)/sup +/ to the equilibrium (H/sub 3/NH...OH/sub 2/)/sup +/ structure. While all the calculations agree on the above points, there are some notable quantitative discrepancies between the various methods. Enlargement of the basis set at the Hartree-Fock level results in higher transfer barriers while subsequent inclusion of electron correlation (POL-CI) leads to barrier reductions. The GVB procedure, with its partial treatment of correlation, produces changes in the potentials opposite to those observed for the more complete POL-CI treatment.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5654976
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:7; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMMONIA
AMMONIUM COMPOUNDS
BARYONS
BOND LENGTHS
CALCULATION METHODS
CHEMICAL BONDS
DIMENSIONS
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
HYDRIDES
HYDROGEN COMPOUNDS
LENGTH
LEPTONS
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUCLEONS
OXYGEN
PROTONS
STRUCTURAL CHEMICAL ANALYSIS
VALENCE