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

New theoretical procedures were proposed for the heats of vaporization (ΔHvap) and sublimation (ΔHsub) 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 ΔHvap, 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 ΔHsub, 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 ΔHvap and ΔHsub predictions could be widely applicable in the areas where accurate chemical information for virtual molecules is critical.