The Kerstboom (Christmas Tree) in Dam Square, Amsterdam
Because the Vrije Universiteit will close down for the period December 24, 2009 - January 3, 2010, the SCM staff will not be reachable during this period. We can also not prepare license files for you during this time. We are back in the office on January 4, 2010. If you urgently need a temporary license file for ADF, you can download it with your username and password. (Windows users should right click on the link then select "Save Link As..." to save this text file.) In case of emergencies, we might still be reachable now and then at "info at scm.com".
The sub-release ADF2009.01b is now available for download from the SCM web site.
Support for new platforms has been added: IBM AIX, SGI Altix ICE with SGI MPT and Cray XT4/XT5 with Cray MPI. The Cray version works with Cray Linux Environment (CLE). A Linux version with Intel-MPI has also been released. In addition, we have confirmed that the Windows versions of ADF run smoothly on the new Windows 7 operating system.
The BAND program has undergone large improvements in speed since its September release. Speed ups in elapsed time of up to a factor of three have been obtained for GGA geometry optimizations of large systems. More improvements are expected in subsequent updates next year.
Based in part on feedback from our users we have also fixed a number of bugs discovered in the prior release. Check the full list of changes for details. As always, any problems with this new release can be reported to support@scm.com.
ADF developer Dr. Marcel Swart has recently been appointed appointed ICREA Research Professor by the Catalan Research Institute (Institució Catalana de Recerca i Estudis Avançats, ICREA). This position allows him to continue working at the Institut de Quíca Computacional of the Universitat de Girona in Spain. An ADF developer throughout his career, Marcel began at the Rijks Universiteit in Groningen where he performed his Ph.D. study on the generation of force fields from density functional calculations, improvement and applications of QM/MM methods in ADF, and calculations of magnetic and optical properties of copper proteins. His postdoctoral works at the Vrije Universiteit in Amsterdam involved a QM/MM study on catalytic cycle of cytochrome P450, and a Density Functional Theory investigation of DNA Replication.
Since moving to Girona, Dr. Swart has been working on understanding and controlling chemical environment effects. His work on the development of ADF also continues, and the latest improvements to his QUILD program will be included with its next release. We congratulate Marcel on his appointment, and wish him the best in this next step of his career.
The World Association of Theoretical and Computational Chemists (WATOC) recently announced that Professor Evert Jan Baerends will receive its 2010 Schrödinger Medal for "his pioneering contributions to the development of computational density functional methods and his fundamental contributions to density functional theory and density matrix theory." The Schrödinger Medal is awarded annually "for the outstanding computational chemist in the world who has not previously been awarded this honor." Professor Baerends has spearheaded the development of density functional theory as a practical tool from the early stages in his career: from the beginnings of what was to become the ADF program in the 1970's through today. He is currently professor at Vrije Universiteit, Amsterdam, as well as Pohang University of Science and Technology in South Korea, and he continues to be a prominent member of the ADF development team.
This makes Professor Baerends the third member of the ADF developers community to be honored by the WATOC. In 2004, Prof. Tom Ziegler (University of Calgary) was also awarded the Schrödinger Medal, and in 2006 Prof. Lucas Visscher (Vrije Universiteit, Amsterdam) was awarded WATOC's Dirac medal.
Johannes Neugebauer, an associate professor at Universiteit Leiden in the Netherlands, has been awarded a Vidi subsidy by the Netherlands Organisation for Scientific Research (NWO). The Vidi award is given to researchers who have demonstrated the ability to successfully work independently and generate new ideas in the years after obtaining their PhD. Bestowed upon researchers regarded as amongst the "top 10 to 20 percent in their field", this subsidy consists of 800,000 euro distributed over 5 years which can significantly aid promising new faculty members in starting their research groups.
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Prof. Neugebauer received his PhD with Bernd Hess at the University of Erlangen-Nürnberg studying theoretical vibrational spectroscopy. After that he worked with E.J. Baerends at the VU Amsterdam and then with Markus Reiher at ETH Zurich, where he obtained the Venia Legendi in Physical Chemistry. His works have included the theoretical study of vibronic coupling effects in spectroscopy, resonance Raman, vibrational circular dichroism and environmental effects. His current research concerns "subsystem-oriented methods for excited states and response properties as well as intensity-driven algorithms for vibrational spectroscopy." This includes the development of a subsystem approach to Time-Dependent DFT related to the Frozen Density Embedding scheme and its application to large systems relevant in photosynthesis. |
We congratulate Johannes on this award and wish him the best in growing his research group.
In a recent edition of Angewandte Chemie, Eva Zurek, now at the University at Buffalo, along with Peter P. Edwards at the University of Oxford and Roald Hoffmann at Cornell University published a detailed computational analysis of lithium - ammonia solutions. The subject of curiosity ever since they were first observed by Sir Humphry Davy 200 years ago, alkali metal - ammonia solutions can be identified in part by their "fine blue colour". The eventual conclusion that these systems were not "metal ammoniums" but rather solutions of alkali cations with the ionized electron distributed in the solvent served to add to the intrigue. Now this unusual electronic state, the brilliant color associated with it and the relationship between the two can be explored with Time-Dependent Density Functional Theory (TDDFT).
Left: Gas-phase orbital energy diagram for Li(NH3)4.
Right: Gas-phase absorption spectrum, simulated by using a Gaussian broadening of 0.2 eV.
The levels involved in the doublet-doublet excitation are shown.
Geometry optimizations of ammonia-solvated lithium ions (simulating bulk solvent with COSMO), as well as computation of the electronic absorption spectra of such systems were done with ADF. Some of the modeling involved radical systems in which a solvated electron is distributed amongst ammonia molecules. Electronic spectrum computations on such open shell systems are not yet commonplace, but the authors were nonetheless able to obtain results that explain the observed visual spectra. Visualization of the modeled spectra and the orbitals involved in the electronic transitions responsible for them are possible with the ADF-GUI. While the connection between the solvated electron and the visible absorbance spectrum of the system has been known for some time, Zurek and her colleagues were the first to establish it using modern computational methods. The exploration of lithium-ammonia solutions conducted in Professor Hoffmann's laboratory is too extensive to be properly illuminated by this brief summary; those who want to know more need only follow the link to the article in Angewandte Chemie.
Mr. Kento Mori et al. of Ryoka Systems Inc., the SCM reseller in Japan, have recently conducted a case study on fac-tris(2-phenylpyridine)iridium (Ir(ppy)3), bis(4,6-difluorophenylpyridinato-N,C2)picolinatoiridium (FIrpic) and bis(2-benzo[b]thiophen-2-yl-pyridine)(acetylacetonate)iridium(III) (Ir(btp)2(acac)), molecules of great interest in the development of Organic Light Emitting Diodes (OLEDs). The results were presented at the 2009 autumn meeting of the Society of Computer Chemistry, Japan (SCCJ). Molecules that are useful for OLEDs are known for a high quantum yield of triplet to singlet phosphorescence in the visible region. These formally spin-forbidden transitions are facilitated through spin-orbit coupling.
Left figure: typical green, blue, and red emitting phosphorescent materials used in OLEDs. Right table: radiative rate constants kr by ZORA-TDDFT calculations with the B3LYP hybrid functional. The experimentally observed trend is correctly reproduced.
The electronic excitations modeled in the table above are a singlet - triplet transitions important to the production of the three colors necessary for the composition of flat screen displays. Two major relativistic effects present in these complexes can be modeled with ADF's ZORA method. The first is the scalar relativistic effect tied to the fast moving electrons in the core region of heavy atoms. The second relativistic effect is spin-orbit (SO) coupling, a phenomenon without which formally spin forbidden singlet - triplet transitions can not occur. The experimental trends for both zero field splitting (ZFS) and the radiative rate constants (i.e. radiative phosphorescence lifetimes) of a whole range of red, green, blue emitters are well reproduced by spin-orbit coupled ZORA time-dependent density functional theory (ZORA-TDDFT) in ADF. ADF is the only program that uses SO self-consistently (i.e. nonperturbatively) during both the SCF and TDDFT parts of the computation. Dr. Erik van Lenthe of SCM, involved in implementing these methods in ADF, provided useful feedback to the Ryoka group during their study.
We have a 17 page Powerpoint presentation with details on this study that is available upon request; contact SCM at info@scm.com. For those who would like to see the presentation file of the study in Japanese, contact either SCM or Ryoka Systems, Inc. at support@rsi.co.jp. Follow-up research involving Mr. Kento Mori et al. in collaboration with Prof. Fan Wang of Sichuan University in China is ongoing; feel free to contact SCM or Ryoka for more information about this work as well.
We always welcome suggestions for new ADF functionality that you would like to see included in a future release. Any questions or comments regarding this Newsletter, or other questions related to ADF, are also 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 or news item on the SCM website.
These news items and more can be found in the news section of our website.
