Lynch Research Group

Our group uses a number of types of spectroscopy to investigate the structure and dynamics of molecules. A few of our projects are listed below.



Iodine

We use laser double resonance to study energy transfer between ion-pair states in diatomic iodine. Specifically we monitor transfer from f to F ion-pair states via emission from the F state down to the B state. This work involves the acquisition of laser spectra of ultra-pure and dry iodine samples, and the subsequent simulation of spectra with computer simulation programs. To the right are sketches of some electronic states of iodine, our double resonance setup, and a sample spectrum and simulation.


MicroWave Spectroscopy

We are interested in working out the structures of small organic molecules using microwave spectroscopy. To date we have had some success working with groups at MIT and the Harvard-Smithsonian Center for Astrophysics, where we obtained what could be a partial microwave spectrum of cis-diazene. Cis-diazene is unstable and very difficult to synthesize; we produced the compound by gentle heating of a stable adduct, shown at right. At Evansville we are in the process of building our own microwave spectrometer using a new technique called "chirping". The chirp applies a broad band of microwave frequencies to the sample allowing the complete microwave spectrum to be acquired instanteously. We hope to use our instrument to obtain microwave spectra of compounds similar to that of cis-diazene.


Molecular Dynamics studied with NMR Spectroscopy

We are presently using temperature-dependent NMR spectroscopy to determine the motion of the cyano group in the compound N-cyano-2,3-diphenylcyclopropenimine. At room temperature the cyano group moves rapidly from one side of the molecule to the other, causing the protons of the two benzene rings to be inequivalent. This causes temperature-dependent splittings in the proton (and carbon-13) NMR spectrum. We have finished the NMR analysis of this compound, but computer simulation of the dynamics has proved difficult; we could not find any simulation programs that would involve the large number of protons in our imine compound. Therefore, we have just completed the synthesis and initial NMR investigation of a similar imine compound in which methoxy groups replace some of the aromatic protons.


Instrumentation in our Lab

People in the Lab

Publications

Awards

Funding Sources