The energetlcs of proton transfer between the N and 0 atoms of (H$WOH& are calculated via ab mltlo molecular orbttal methods A smgle-well potentgal IS obtamed at the equhbnum mternrolecuiar separation ~nch.~s~on of electron corcehtxon via the POL CI techmque produces a Iess steep potent&. rc lucmg t
Energetics and electronic rearrangements of proton transfer in (H3NHOH2)+
✍ Scribed by Steve Scheiner
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- English
- Weight
- 597 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
Abstract
Proton transfer between N and O in the hydrogen‐bonded system (H~3~NHOH~2~)^+^ is studied by ab initio molecular orbital methods. Potential energy curves are calculated at the hartree–Fock level using the 4–31__G__ basis set for hydrogen bond lengths R(NO) varying from the equilibrium value of 2.664 to 3.10 Å. Short hydrogen bonds are associated with asymmetric single‐well potentials in which the minimum corresponds to the NHO configuration. For longer R(NO) separations, the potential is of double‐well form, including both NHO and NHO as minima. It is found that the height of the energy barrier to proton transfer is sensitive to both stretches and bends of the hydrogen bond. Continuous changes in the electron density are monitored at various stages of proton transfer via density difference maps and Mulliken population analyses. The initial loss of density from the proton‐accepting molecule during the first half of the transfer is accelerated during the second half. A correlation is drawn between the energetics of transfer in a number of systems and the net charge lost by the proton‐acceptor group.
📜 SIMILAR VOLUMES
Quantum mechanical ab initio calculations at the MP2/6-3 lG\* level are performed on two proton bound dimer systems, [HsN-H-NHs]+ and [ H2N-H-OH,] +. Several calculations using a medium-size polarized basis set were performed as a check of the 6-3 IG\* results. Energies are calculated at heavy-atom
We have studied the quantum dynamics of proton transfer in the hydrogen-bonded complex HaOf-Ha0 using a previously computed three-dimensional potential energy surface. The two coordinates considered are the distance of the hydrogen atom from the O-O midpoint and the O-O distance, for a linear O-H-O