| Abstract: | We present a new implementation of the polarizable continuum model (PCM) that significantly improves its performance, especially for large solutes. This approach avoids the separation between electronic and nuclear sources in the calculation of the solvation charges, allowing the extension of iterative procedures to all the PCM versions [dielectric (D), conductor (C), and integral equation formalism (IEF)], so that the best method and/or algorithm can be selected, depending on the system at hand. In particular, the new balanced two-term iterative procedure with total charges avoids any nonlinear computational step and memory occupation. Furthermore, it also shows a good convergence for the C-PCM and IEF-PCM versions, which were quite problematic for the conventional separate charges approach. Also, first and second analytical derivatives are available in this context for Hartree–Fock and Kohn–Sham models. A number of examples are analyzed; they show that the new algorithms couple fully satisfactory numerical accuracy with remarkable computational efficiency. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1186–1198, 1999 |
