With this award from the Chemistry Research Instrumentation and Facilities Instrument Development program, Professor Stephen Kukolich of the University of Arizona will develop a pulsed-beam, Fourier-transform microwave spectrometer to measure rotational transition frequencies for transition metal complexes, hydrogen-bonded complexes, and other molecules in the 1 to 10 GHz region of the microwave spectrum. Unlike previous pulsed-beam FT microwave spectrometers, this will allow measurement of frequencies below 4 GHz, which is very important for large molecules. Large molecules have complicated rotational spectra for transitions originating from high rotationally excited states (high J states), making such spectra difficult to assign. Transitions from rotationally cold states (low J states) of large molecules are simplified and less congested, but access to such transitions has been limited, since some of these transitions fall in the technologically inaccessible spectral region below 4 GHz. The proposed instrument would be able to access this region, and thus enable assignment of rotational spectra and determination of molecular geometries of large molecules.
The spectrometer will enable structure and quadrupole coupling measurements for: 1) dinuclear transition metal complexes, 2) larger hydrogen bonded complexes chosen to model interactions in biological systems, such as base-pair recognition and protein folding, 3) transition metal complexes with larger ligands, and 4) other molecules of biological interest. The proposed research projects will be carried out with collaboration and participation of graduate and undergraduate students at The University of Arizona. Participation in the research projects will allow the students to gain experience and knowledge in the fundamentals of chemistry, quantum mechanics, computer technology, microwave electronics, spectroscopy, and making physical measurements.
