Subject: New AMSOL avail. from QCPE

From: <[email-masked]>
Date: Sun, 7 Aug 94 14:45:45 CDT

The following announcement for version 4.5 of AMSOL will appear 
shortly in QCPE Bulletin, Volume 14, page 55 (1994). The code is 
immediately available from QCPE (non-profit, of course).

NEW VERSION ANNOUNCEMENT: AMSOL-version 4.5

   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 (not included in this e-mail post).  

   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.