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ADF Newsletter, December 2005
The ADF-team wishes you all the best for 2006!
ADF developments
- Improved analytical second derivatives of energy
- QM/MM with ADFinput
ADF 2005 release
- Faster gradients and other speed improvements
- Improved modules for the ADF Graphical User Interface
- Improved geometry optimization and transition state search methods
Other News
- Evert Jan Baerends Symposium
- ADF2005 conference tour
- ADF at ACS meetings, 2006
Improved analytical second derivatives of energy
Analytical second derivatives (SD) have been available in ADF for a long time but they were restricted to LDA only. In our development version it has been extended to the most popular GGA's. The full list of functionals supported at this moment in our development version:
- Exchange: Becke88, PBEx, RPBEx, revPBEx, OPTX
- Correlation: LYP, PBEc
Other improvements are:
- The SD code has been integrated in ADF so it is no longer necessary to run a separate SD program
after main ADF. - It will be possible to calculate frequencies after geometry optimization in one job.
- The speed of the code has been improved. For most types of calculation a factor of 3 speed-up with
respect to the usual ADF frequency calculation is easily achieved. - The new SD is not only faster than the traditional ADF frequency code but it is also more accurate,
especially at lower integration accuracy parameters.
Speed comparison for the new SD code
The benchmark system is a 45-atom organic molecule without symmetry. Calculations were done in all-electron Double-zeta basis set with integration accuracy 5 and the BLYP exchange-correlation potential. The tests were performed on a 8-processor 2.2GHz Opteron machine with 32GB of shared memory. A frequency calculation with ADF2005 took 11.8 hours while the new SD code was finished in 3.8 hours.
QM/MM with ADFinput
The QM/MM method has been available within ADF for some time now. We are working on making the QM/MM method also available through ADFinput, part of the ADF-GUI.
Right now the focus is to enable handling of proteins. PDB files are read (using the same method as pdb2adf uses), and the user can tune some details of the protein. And of course the user can select what part of the protein to handle at the QM level. The protein and QM part are shown graphically. We expect this feature will be available in the next release of the ADF-GUI.
ADF 2005 release
Some major improvements with respect to the 2004 version include:
- Significant improvements in ADF graphical user interface, more powerful visualization and input builder
- Delocalized coordinates and Nudged Elastic Band methods for geometry optimization and transition state search
- Faster gradients for large molecules and faster analytic second derivatives (for VWN functional)
- Open-shell TDDFT, including spin-flip excitations
- More accurate numerical frequency calculations
- Several other enhancements
A bug has been discovered that affects the results of certain types of NMR calculations with ADF2004 and older versions, which has been fixed in ADF2005.
Evert Jan Baerends Symposium
To honour his achievements in Theoretical Chemistry, an international symposium on the occasion of the sixtieth birthday of Evert Jan Baerends was held in Amsterdam, November 4, 2005.
Prof. Dr. Eberhard Gross, Prof. dr. Angela Rosa, Prof. dr. Tom Ziegler, Dr. Robert van Leeuwen, Dr. Trond Saue, Prof. dr. Miquel Solà, and Prof. dr. Ad van der Avoird gave talks on various aspects of Density Functional Theory and its applications in chemistry. In the after dinner talk Dr. Pier Philipsen took us on a voyage with the Beagle.
ADF2005 conference tour
Recently SCM was at the following conferences:
- ACS meeting, Washington, August 28 - September 1, 2005, and ADF workshop, August 30th.
- DFT2005 conference, Geneva, September 11-15.
- Chinese national quantum chemistry meeting, Guilin, October 8-12, 2005,
invited by HongCam - Pacifichem 2005, Honolulu, December 15-20, 2005.
ADF at ACS meetings, 2006
SCM will be present at the ACS meetings in Atlanta, March 26-30, 2006, and San Francisco, September 10-14, 2006. Visit us to learn more about the upcoming improvements in ADF and anything else you would like to know about ADF.
Questions, comments, contributions
Any questions or comments regarding the above, or other questions related to ADF, are very welcome and can be sent to info@scm.com. Feel free to contact us also in case you have some information that may be of interest to other ADF users, and that may be suitable material for a future Newsletter.
