Improving Quantum Chemical Solvation Models by Dynamic Radii Adjustment for Continuum Solvation (DRACO)

We present the Dynamic Radii Adjustment for COntinuum
solvation
(DRACO) approach, which employs precomputed atomic partial charges
and coordination numbers of the solute atoms to improve the solute
cavity. As such, DRACO is compatible with major solvation models,
improving their performance significantly and robustly at virtually
no extra cost, especially for charged solutes. Combined with the purely
electrostatic CPCM and COSMO models, DRACO reduces the mean absolute
deviation (MAD) of the solvation free energy by up to 4.5 kcal mol–1 (67%) for a large data set of polar and ionic solutes.
Even in combination with the highly empirical universal solvation
model (SMD), DRACO substantially reduces the MAD for charged solutes
by up to 1.5 kcal mol–1 (39%), while neutral solutes
are slightly improved (0.2 kcal mol–1 or 16%). We
present an interface of DRACO with two computationally efficient atomic
charge models that enables fully automated, out-of-the-box calculations
with the widely used program packages Orca and TurboMole.