The transfer of a proton from A to B in AH+‥B‥C to form A‥+HB‥C is expected to enhance the binding energy of C to the remainder of the H-bonded chain since C is now adjacent to a charged ion rather than to a neutral molecule. But since the actual proton motion between A and B is typically only 1 Å or so, the interaction should be considerably less than that in isolated +HB‥C. Ab initio calculations with a variety of basis sets are used to quantitatively measure the enhancement of this binding energy. Systems investigated include the homotrimers of water and of ammonia, ammonium–formate–water, and formic acid–imidazole–water.
- hydrogen bond,