Stretching frequency vs bond distance correlation of hydrogen bonds in solid hydrates: A generalized correlation function

Supplementary uncoupled <(nu)over bar>(OD) frequencies of isotopically dilute HDO molecules (from 75 K IR measurements) are reported for O-H(D)... Cl and O-H(D)... Br hydrogen bonds in solid hydrates that improve the statistical significance of the corresponding frequency vs. R(O ... Y) distance correlations. The question of establishing a uniform frequency vs. distance correlation function that is approximately valid for all kinds of O ... Y hydrogen bonds in solid hydrates is reconsidered. It is shown that the previous single correlation functions, which contain two physically meaningless Y-dependent regression parameters, can consistently be replaced by a uniform correlation function, which, besides general parameters, contains the electronegativity and an appropriately defined hydrogen bond contact radius, r(HB) (Y), Of the Y-proton accepters.