Hydrogen bonding classical limits

As is obvious from the table, Tc is almost doubled upon deuteration. These isotope effects are one of the largest observed in any solid state system. The question arises about isotope effects in non-hydrogen-bonded ferro- and antiferroelectrics. As already mentioned in the Introduction, within a mean-field scheme and in a purely ionic model it was predicted that these systems should not exhibit any isotope effect in the classical limit, which has been verified experimentally. Correspondingly, there was not much effort to look for these effects here. However, using a nonlinear shell-model representation it was predicted that in the quantum limit an isotope effect should... 

It is known that first principles molecular dynamics may overcome the limitations related to the use of an intermolecular interaction model. However, it is not clear that the results for the structure of hydrogen bonding liquids predicted by first principles molecular dynamics simulations are necessarily in better agreement with experiment than those relying on classical simulations, and recent first principles molecular dynamics simulations of liquid water indicated that the results are dependent on the choice of different approximations for the exchange-correlation functional [50], Cluster calculations are an interesting alternative, although surface effects can be important and extrapolation to bulk phase remains a controversial issue. 

With reference to hydrogen bonding, I have recently found that the three-body term can have an important and profound influence on the effective AB-bond due to hydrogen in the AHB system. The sensitivity of the hydrogen bond to parameters in the AH and BH potentials is greater than one would expect on the basis of the influence of the term on classical limit properties [unpublished]. 

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