From chemistry-request@ccl.net Mon Sep 23 08:54:40 1991 Date: Mon, 23 Sep 1991 08:40 EDT From: "DOUGLAS A. SMITH" Subject: Postdoctoral position To: chemistry@ccl.net Status: R Postdoctoral Position in Computational Organic Chemistry A one-year position (start date 12/1/91 - 1/15/92) is available to study the nonlinear optical properties of organic molecules using semiempirical and ab initio molecular orbital methods. In particular, we are studying the relationships between the applied field vector used for the calculations, the perturbations in the molecular orbitals and densities, and the first and second hyperpolarizabilities. Visualization and animation of these effects using AVS is a key part of this work. Potential candidates for the position should have a PhD in Computational or Theoretical chemistry, with a working knowledge of Organic chemistry, and experience with MOPAC, AMPAC, or an ab initio package such as Gaussian 90. A PhD in Organic chemistry with suitable molecular modeling experience would also be acceptable. Knowledge of or experience in molecular dynamics is a plus. Skill with UNIX, FORTRAN and C is important for rapid progress, since this project will involve some code development and optimization. Interested persons should send a curriculum vitae, reprints/preprints, and at least two (2) letters of recommendation to: Dr. Douglas A. Smith Department of Chemistry The University of Toledo Toledo, OH 43606-3390 voice 419-537-2116 fax 419-537-4033 email fax0236@uoft02.utoledo.edu This work is supported by Cray Research, Inc. and the Ohio Supercomputer Center. From chemistry-request@ccl.net Mon Sep 23 10:43:52 1991 Date: 23 September 1991 09:22:19 CDT From: "Bob Goldstein 6-6664" To: Subject: fast heating Status: R In regard to Mike Lee's question about fast heating, it seems to me 1 ns is actually quite a long time, although it may depend on exactly what "heating" means in this case. There are certainly cases in which vibrations can become excited some ps after electonic absorption. For example, rhodopsin undergoes a cis-trans isomerization in less than 1 ps. The Raman spectrum of myoglobin changes in less than 10 ps when CO is photodissociated (and in this case, it is the heme, not the Fe-CO bond, that absorbs the light). Photosynthetic reaction centers can transfer an electron in 3 ps, and this surely leaves some vibrations in excited states. So there are cases in which the electron-phonon coupling is large enough to transfer energy in much less than 1 ns (which is, after all, a long time compared to a vibrational period). But whether or not all the vibrational modes are fully thermallized may be a different question. Bob Goldstein