CHIRPED PULSE AND CAVITY FOURIER TRANSFORM MICROWAVE (CP-FTMW AND FTMW) INVESTIGATIONS INTO 3-BROMO-1,1,1,2,2-PENTAFLUOROPROPANE; A MOLECULE OF ATMOSPHERIC INTEREST NICHOLAS FORCE, DAVID JOSEPH GILLCRIST, CASSANDRA C. HURLEY, FRANK E MARSHALL, NICHOLAS A. PAYTON, THOMAS D. PERSINGER, N. E. SHREVE, and G. S. GRUBBS II TE05, International Symposium on Molecular Spectroscopy 69th Meeting - Champaign-Urbana, Illinois

Outline Driving Forces Background Information Experimental Methods CP-FTMW Details CP-FTMW Problems Theory Data and Results Future Work

Driving Forces Good test subject for the inauguration of a newly constructed Chirped Pulse Fourier Transform Microwave (CP-FTMW) spectrometer at MS&T

Driving Forces Atmospheric interest as a replacement solvent/refrigerant for CFCs Beginning of a series of studies with OH●

Background Information Boiling Point: 46.5 °C Molecular Weight: 212.94 a.u. Density 1.756 g/mL

Experimental Methods CP-FTMW spectrometer and FTMW spectrometer Purchased directly from SynQuest Labs® and used without further purification Bubbled Ar at ≈2 atm through sample in a “U”-shaped tube in ice ≈40 cm upstream from nozzle

CP-FTMW Details 6-18 GHz frequency range Goal to simplify circuit to make the spectrometer as robust as possible for ease of use This is accomplished through the Tektronix® 50 GS/s, 20 GHz AWG70001A and 100 GS/s, 23 GHz DPO72304DX Oscilloscope Vacuum Chamber

CP-FTMW Details

CP-FTMW Problems AWG70001A does not come with a marker editing feature as of yet (even in RFXpressTM software); this is supposed to be corrected in software July 2014 Have addressed by taking chirp pulse code and using MatLab® codes and by brute force with a .txt 10-bit code; getting the sequencing option for the AWG Leaks

Theory Parameter Value A /MHz 2375.2 B /MHz 545.9 C /MHz 538.4 a dipole -0.98 D b dipole 2.31 D c dipole 0 D Calculations made at the MP2/6-311++G level on the Gaussian03®, Revision C.1 suite

Results and Data Used theoretical constants in SPCAT1 and AABS2 to predict and sort where to start search on FTMW while CP-FTMW was being constructed Search started in the 10845-10870 MHz region where there are predicted many J = 10 – 9, a-type and J = 5 – 4, b-type transitions H. M. Pickett, J. Mol. Spectrosc. 148, 371 (1991). Z.Kisiel, L.Pszczolkowski, I.R.Medvedev, M.Winnewisser, F.C.De Lucia, E.Herbst, J.Mol.Spectrosc. 233,231-243(2005)

Results and Data Doppler split transitions found and gas-dependent! (all spectra ≤500 nozzle pulses)

Future Work Address CP-FTMW Problems Collect More Spectra Fit and Assign Spectra Continue to Setup Laboratory

Acknowledgements Startup funds from MS&T University of Missouri System Research Board Grant Pete Pringle, Stew Novick, Steve Cooke, and Brian Howard