George McBane Research Interests
I enjoy teaching and studying physical chemistry and chemical physics. My research efforts up to about 2005 concentrated on intermolecular forces; the questions are "What are the shapes of small molecules? How sticky or hard are they? What are the forces that push them around?" I have used both experiments (primarily based on molecular beams and lasers) and calculations to try to answer these questions. Since 2005 I have broadened the computational work to include the intramolecular forces acting during ordinary chemical reactions, during photodissociation, and during collisions at ultralow temperatures. This recent work was carried out in large part in collaboration with R. Schinke and with J. Hutson.
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I have research projects in progress in the following areas:
- Determination of pressure broadening coefficients of vibrational overtone lines using a diode laser near-infrared spectrometer.
- Computational investigations of molecular collisions and photodissociation, using both classical and quantum mechanics.
- Development of new algorithms and programs for accurate fully-quantum calculations of collision properties.
The primary instrument used in our spectroscopic work is a very high spectral resolution, high sensitivity, absorption spectrometer that works in the region of 1600 nm. Its light source is an external cavity diode laser. At present we use a multipass Herriot cell to study pressure broadening effects on overtone infrared lines. This work is carried out in collaboration with Professor Stephanie Schaertel.
Students with interests in computational work and computer programming may enjoy computational projects. These projects involve both electronic structure calculations and dynamics and kinetics calculations that describe the motions of the atoms during collisions and reactions. We use both classical and quantum mechanical models. For the calculations we use the computational cluster in the chemistry department and national supercomputer facilities. Several projects involve collaborations with experimental and theoretical research groups around the world. One current computational project is a study of the quenching of electronically excited oxygen in the atmosphere.
I also enjoy playing pool. The photograph above was taken by Bernadine Carey-Tucker for a piece in Grand Valley Magazine.
Textbook
Arthur Halpern of Indiana State University and I published a book, Experimental Physical Chemistry: A Laboratory Textbook, 3rd edition (2006). The hardback book is out of print but the individual experiments are available from the LabPartner link above. The opening chapter on data collection, data analysis, and reporting of results has now been restored and can be included in the LabPartner version. An Instructor's Manual is available to course instructors, giving help on purchasing and constructing experimental hardware and carrying out the experiments; contact me for a copy.
The book was accompanied by a free program ("SDAS") that extends Microsoft Excel to perform most of the data analysis tasks required in the physical chemistry laboratory, including nonlinear fits with good treatment of the errors in data and fitted parameters. Arthur Halpern and colleagues have now published a description of a newer version of this program called SDAT, and the installation files are available as supplementary information from their article; see Arthur M. Halpern, Stephen L. Frye, and Charles J. Marzzacco, J. Chem. Educ. 95(6), 1063 (2018) DOI:10.1021/acs.jchemed.8b00084.
Lecture notes
Chemistry 353/355/455 (the "green book")
Lecture notes and handbook for statistical treatment of data in the physical chemistry laboratory. These were primarily developed for Chemistry 541 at Ohio State, and are now available to students at GVSU.
Lecture notes for a graduate chemical kinetics course. These are in much cruder form than the data analysis notes. There are strong echoes of several textbooks: Steinfeld, Francisco, and Hase, Chemical Kinetics and Dynamics, 2nd ed. (Prentice-Hall, 1999); Espenson, Chemical Kinetics and Reaction Mechanisms, 2nd ed. (McGraw-Hill, 1995); and Laidler, Chemical Kinetics 3rd ed. (Harper and Row, 1987). Hand drawn figures (many) are missing. This is the result of the first attempt to put these notes in electronic form.
Lecture notes for the first-term physical chemistry course from fall 2015. This course is essentially an introduction to quantum mechanics with applications to atoms and molecules.
Lecture notes for the second-term physical chemistry course from winter 2016, covering kinetics, thermodynamics, and a few other topics.
Available software
PMP Molscat is a parallelized version of the Molscat quantum scattering program of Hutson and Green. It uses the MPI message passing library. It also includes a utility that permits "poor man's parallel" calculations without any message passing harness at all.
Virial6 is a Fortran program for evaluating interaction second virial coefficients for atom-diatom or diatom-diatom mixtures. It calculates the classical and all first order quantum corrections, and the radial second order quantum correction. The zip file contains the Fortran source, a makefile, and sample input and output files. As provided it uses the H2-CO potential of Jankowski and Szalewicz (JCP 108, 3554 (1998)). The original J&S potential evaluation function has been heavily modified to eliminate redundant angular calculations, and the new "vector" evaluation routines are included. Other potentials may be used by writing simple wrapper functions to let them communicate with virial6. Users will need a BLAS library, or will need to download and compile the double precision real BLAS routines from Netlib and link them with this program.
Vector H2-CO potential routines
This zip file contains several Fortran routines for rapid evaluation of the Jankowski and Szalewicz H2-CO potential, and a modified MOLSCAT/BOUND "potenl" routine that uses them. Comments are sparse but perhaps sufficient. An example BOUND input file and corresponding output are also included.
Imsim
Imsim is a Fortran program that generates images expected from crossed-beam scattering experiments with laser photoionization and 2D velocity mapping detection. The current version is 2.0, which is very much faster than earlier versions if realistic averaging over the molecular beam speed distributions is desired. To install it, place the zip file in its own directory, unzip it, and then read either imsim.tex or imsim.html for further instructions. The files use Unix end-of-line conventions; if you are on a PC, you probably want to use unzip.exe and unzip with the command
unzip -a imsim.zip
which will convert to the PC convention. New features in recent Imsim versions include: (1) much faster velocity averaging, (2) a rudimentary option for testing the effects of extreme v-j correlation on the images, (3) the possibility of generating many images in a single Imsim run, including "palettes" of images for least squares fitting, and (4) a prepackaged Fortran BLAS file to ease installation. The "edge pixel" problem was fixed in version 1.3.
Imsim, and its accompanying image fitting program (never released publicly) have returned to active development as of August 2008 after a dormant period of several years. If you are interested in them, please contact me by email so I can let you know about recent developments.
As of 2 May 2018 there is a beta version, Imsim3 . It permits modeling of bimolecular reactions (A + B -> C + D), slice imaging, and photoexcited colliders, and lets users enter changes in internal energy directly rather than computing them from simple rigid-rotor formulas. Output images will not be bitwise-identical to the old version for identical inputs, because I also changed the procedure used to determine the limits on the integration over time before the laser pulse. However, I do not expect (and would like to be told about!) any changes large enough to be physically meaningful.
[GVSU is committed to making all resources accessible to those with disabilities. If you have a disability that prevents you from using these software packages, please contact me directly ([email protected]) so that I can help you obtain what you need].