A probe on the intermolecular forces in diisopropyl ether-n-butyric acid mixture by dielectric, FTIR studies and quantum chemical calculations

► Non-linearity of εm Vs X2 curve due to hetero H-bond formation - to be corrected. ► No evidence for geff to be the index of H-bonding ability of solute/solvent. ► Positive εE values - increase in the number of effective dipoles also seems invalid.