1. 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

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

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

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

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

6. 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

7. 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

8. CP-FTMW Details

9. 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

10. 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/ G level on the Gaussian03®, Revision C.1 suite

11. 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 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, (2005)

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

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

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