A priori prediction of heats of vaporization and sublimation by EFP2-MD

New theoretical procedures were proposed for the heats of vaporization (ΔH_vap) and sublimation (ΔH_sub) predictions by adopting effective fragment potential version 2-molecular dynamics (EFP2-MD) simulations. The particular EFP2, as generated by HF/6-31++G(2d,2p), yielded excellent results in the predictions of ΔH_vap, where mean absolute deviation (MAD) and root-mean-square deviation (RMSD) for 16 molecules were 0.34 and 0.44 kcal/mol, respectively. By introducing a uniform scaling factor, we further derived a prediction procedure for ΔH_sub, where its MAD and RMSD were 0.76 and 0.90 kcal/mol, respectively. Because EFP2-MD does not require any ab initio computations during simulation, computational overhead of our procedures is minimal. We believe that our new procedures for the ΔH_vap and ΔH_sub predictions could be widely applicable in the areas where accurate chemical information for virtual molecules is critical.