2002 NASA/ASEE Faculty Fellow working in the Technology Implementation Branch, Spaceport Engineering and Technology,
John F. Kennedy Space Center
B.A. Williams College
M.A. Princeton University
Ph.D. Princeton University
Dr. Baum has more than 40 years of experience in molecular spectroscopy including postdoctoral research at Florida State University. He has been a NASA/ASEE Faculty Fellow involved in research at the John F. Kennedy Space Center. He has been an instructor in summer courses for industrial, academic and government scientists on "Fluorescence Spectroscopy: Techniques and Applications". Dr. Baum has taught courses in undergraduate and graduate physical chemistry and general chemistry at Florida Tech for more than 30 years.
Â· Hydrogen bonding occurs in the structure or environment of many biological systems. Therefore, much of our research is focused on the influence of hydrogen bonding on the spectral properties of molecules and an understanding of how hydrogen bonds are affected when a participating molecule is excited to various electronic levels by the absorption of light. For example, the role of hydrogen bonding in emission quenching and molecular recognition is being explored. Hydrogen-bonded systems capable of energy transfer have been found to display an unusual degree of quenching. The competition between energy transfer, electron transfer, proton transfer and hydrogen atom transfer is being examined. This project involves the synthesis by Dr. Alan Brown's research group of novel molecules that contain matched donor-acceptor pairs and photophysical studies of these molecules by our group. Another project involves a series of compounds that allows a comparison of sulfur versus oxygen in hydrogen bonding.
Â· There are several other collaborations within our department that involve molecular modeling. For example, we are modeling tryptanthrin and its derivatives adsorbed on graphite, with synthesis by Dr. Mark Novak's group and STM studies by Dr. Joel Olson's group. In the process we have experimentally verified the validity of the most recent quantum mechanical models. We are investigating the mechanisms of reactions involving ferrates with Dr. Virender Sharma's group and the mechanism for the enzyme degradation of sulfenium ions related to mustard gas with Dr. Novak's group. We have modeled the transition states and explained the reaction rates of a series of organometallic compounds synthesized and studied by Dr. Rudi Wehmschulte.
Â· Another goal is to develop sensors that are sensitive, selective, reversible and provide real-time measurements. The combination of fluorescence (which is sensitive and selective) and hydrogen bonding (which is selective and reversible) should allow this aim to be accomplished. One project involves the development of a sensor for the low-level detection of hydrazine. Another sensor simultaneously detects the presence of hydrazine and nitrogen dioxide, hazardous compounds that are part of the propulsion system for the Space Shuttle orbiter as well as other spacecraft and missiles.
"Laser Measurement of the Speed of Sound in Gases. A Novel Approach to Determining Heat Capacity Ratios and Gas Composition", J.C. Baum, R.N. Compton, C.S. Feigerle, J. Chem. Educ., 85, 1565 (2008).
"Scanning Tunneling Microscopy of
8-Fluoroindolo[2,1-b]quinazolin-6,12-dione (8-Fluorotryptanthrin) at the Graphite-Solution Interface: Fully Resolved Molecular Orbitals.", R.E. Gilman, M.J. Novak, J.C. Baum, J.A. Olson, J. Phys. Chem. C, 112, 14545 (2008).
"A Fluorescence Technique to Determine Low Concentrations of Ferrate(VI)", N.N. Noorhasan-Smith, V.K. Sharma, J.C. Baum, in "Ferrates. Synthesis, Properties and Applications in Water and Wastewater Treatment", V. Sharma, Ed., ACS Symposium Vol. 985, p. 145. (2008)
"Size Matters: Room Temperature P-C Bond Formation Through C-H Activation in m-Terphenyldiiodophosphines", A.A. Diaz, B. Buster, D. Schomisch, M.A. Khan, J.C. Baum, R.J. Wehmschulte,Inorganic Chemistry, 47, 2858 (2008).
"Ferrate(VI) and ferrate(V) oxidation of cyanide, thiocyanate, and copper(I) cyanide,V.K. Sharma, R.A. Yngard, D.E. Cabelli, J.C. Baum, Rad. Phys. Chem., 77, 761 (2008).
"Scanning tunneling microscopy of indolo[2,1-b]quinazoline-6,12-dione (tryptanthrin) on HOPG: Evidence of adsorption-induced stereoisomerization", M.J. Novak, J.C. Baum, J.W. Buhrow, J.A. Olson, Surface Science 600, 269 (2006).
"Fluorescent-enhancement sensing of ammonia and hydrazines via disruption of the internal hydrogen bond in a carbazolopyridinophane", A.B. Brown, T.L. Gibson, J.C. Baum, T. Ren, T.M. Smith, Sensors and Actuators B 110, 8 (2005).
"Hydrazine/nitrogen dioxide fiber optic sensor", A.S. Andrawis, J. Santiago, R.C. Young and J.C. Baum, Proceedings of the SPIE, 5502, 239 (2004).