Old Release Notes

C. J. Cramer, G. D. Hawkins, G. C. Lynch, D. J. Giesen, D. G. Truhlar, and D. A. Liotard, QCPE Bulletin 1994, 14, 55.


A new version of AMSOL, version 4.5, is now available. This is a revision of version 4.0, for which the reference is QCPE Bulletin, Volume 13, page 78 (1993). The new version will be cataloged by QCPE as program 606-version 4.5. QCPE received version 4.1 in June and distributed that version in June and July. QCPE received version 4.5 in early August and began distributing it immediately. To determine whether you need to or wish to update your version, consult the version number in your current copy as well as the following summary of major revisions and enhancements in recent versions of AMSOL:

3.0 First version with SM2 and SM3 solvation models.

3.0.x Bug fixes. Improved portability.

3.5 Improved efficiency in the original algorithm for calculating solvent-accessible surface areas (SASAs). A new option (GEPOL) for calculating SASAs. Flexibility options allowing precision vs. computer-time tradeoffs in SASA calculations. More convenient user control of dimensions.

3.5.x Bug fixes.

4.0 A new option (ASA) for analytic calculation of SASAs. Two new options for convergence strategies for gas-phase and aqueous SCF calculations. A new option to use the GEPOL algorithm to calculate molecular volume.

4.0.x Bug fixes.

4.1 The SM2.1 model is added. This model uses the force trapezoid algorithm for radial integrations in the dielectric screening algorithm; this algorithm is faster and more stable, improving SCF convergence. New options for external input of atomic charges and/or solvation parameters.

4.1.1 Minor bug fixes.

4.5 A new option is added for calculating class IV atomic charges of gas-phase molecules by the CM1A and CM1P models. These models are based on a new semiempirical approach that provides meaningful atomic charges (comparable in accuracy to MP2/6-31G* electrostatic fitting charges) with computational effort essentially equivalent to the cost of an AM1 or PM3 calculation.

The reader should be alerted to the significant speedups in recent versions. The following table gives typical speedups of version 4.5 relative to version 3.0.1 (all timings are for runs including geometry optimization in aqueous solution; each column is separately normalized):

Unix workstation Cray supercomputer

version 3.0.1, SM2 or SM3 1 1

version 4.5, SM2 or SM3 26 5

version 4.5, SM2.1 30 7

An updated program description for version 4.5 is given on the following pages.

The authors of AMSOL expect to have SM4 solvation models available for both aqueous and alkane solvents (all noncyclic alkanes, pentane through heptadecane) in a later version of AMSOL, probably in version 5. These solvation models are being parameterized using the new charge models.

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