Department of Medicinal Chemistry, Medical University of Lublin, Poland. PAULINA M CZKA .... to Y2101 cmY1 of very high intensity (1069.89) associated with a proton transfer path. ... Introducing the proton free energy (equal to Y26.7 kJ/mol), free .... Beckett A.H., Stenlake J. B.: Practical Pharmaceutical Chemistry, Vol.