Potential energy surface hydrogen bond

Fig. 2.10 The stationary points on the propane potential energy surface. Hydrogens at the end of CH bonds are omitted for clarity...

D. A. Dixon, R. M. Stevens, and D. R. Herschbach, Potential energy surface for bond exchange among three hydrogen molecules, Faraday Disc. Chem. Soc. 62 110 (1977). 

The origin of a torsional barrier can be studied best in simple cases like ethane. Here, rotation about the central carbon-carbon bond results in three staggered and three eclipsed stationary points on the potential energy surface, at least when symmetry considerations are not taken into account. Quantum mechanically, the barrier of rotation is explained by anti-bonding interactions between the hydrogens attached to different carbon atoms. These interactions are small when the conformation of ethane is staggered, and reach a maximum value when the molecule approaches an eclipsed geometry. 

Because FHF- epitomizes the limit of strong hydrogen bonding in a particularly simple geometrical form, let us examine some further aspects of its potential-energy surface. The triatomic species can generally be described in terms of three variables,... 

C. S. Callam, S. J. Singer, T. F. Fowary, and C. M. Hadad, Computational analysis of the potential energy surfaces of glycerol in the gas and aqueous phases Effects of level of theory, basis set, and solvation on strongly intramolecularly hydrogen bonded systems. J. Am. Chem. Soc. 123, 11743 11754 (2001). 

In general, an hydrogen atom in an hydrogen bond can be considered as having available to it two wells in the potential-energy surface, corresponding to two possible states of the system ... 

One such feature is the potential energy surface for proton transfer in the contracted hydrogen bonds. The time-averaged potential surfaces are almost symmetrical (especially for the Zundel ion) without significant barriers, i.e., the proton is located near the center of the bond. Whether its location is off-center at any time instance is mainly dependent on the surrounding hydrogen-bond pattern, and it is the... 

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