High Resolution Broadband Rotational Spectroscopy Ground State Spectrum

High Resolution Broadband Rotational Spectroscopy: Ground State Spectrum of 1 -chloro-1 -flouroethylene Kelly M. Hotopp Purdue University

Chirped Pulse Fourier Transform Microwave (CP-FTMW) Spectroscopy 2 -D Rotational Spectroscopy Broadband CP-FTMW Rotational Constants and Structural Information

Pulse Generation 1) Pulse Generation 100 MHz Quartz Oscillator Chirped Pulse 1. 875 -4. 625 GHz Arbitrary Waveform Generator 20 d. B x 4 2) Interaction 7. 5 -18. 5 GHz Pulsed Sample Nozzle Free Inductive Decay 200 W 40 d. B LNA: 1. 2 -1 12 GHz Oscilloscope (40 Gs/s) 3) Detection 18. 9 GHz PDRO

Chirped Microwave Pulse (linear frequency sweep) Full Sweep Time Domain Full Sweep Frequency Domain

Phase Control Phase of the excitation pulse is imprinted on the molecular emission.

Molecular Interaction Region 1) Pulse Generation 100 MHz Quartz Oscillator Chirped Pulse 1. 875 -4. 625 GHz Arbitrary Waveform Generator 20 d. B x 4 2) Interaction 7. 5 -18. 5 GHz Pulsed Sample Nozzle Free Inductive Decay 200 W 40 d. B LNA: 1. 2 -1 12 GHz Oscilloscope (40 Gs/s) 3) Detection 18. 9 GHz PDRO

Experimental Set-up Supersonic Expansion Cools Molecules ~ 2 K Pulsed Valve Ultrabroadband MW Input XYZ Translation Stage Manual Balle. Flygare FTMW Cavity UV Input

Detection 1) Pulse Generation 100 MHz Quartz Oscillator Chirped Pulse 1. 875 -4. 625 GHz Arbitrary Waveform Generator 20 d. B x 4 2) Interaction 7. 5 -18. 5 GHz Pulsed Sample Nozzle Free Inductive Decay 200 W 40 d. B LNA: 1. 2 -1 12 GHz Oscilloscope (40 Gs/s) 3) Detection 18. 9 GHz PDRO

Ground State Spectrum of 1 -chloro-1 flouroethylene n 476 lines assigned to date n ~ 18, 000: 1 S/N across entire bandwidth (rms) n ~12, 000: 1 S/N (Pk to Pk) n Lines split by nuclear hyperfine of Cl n Background subtracted with valve off n 13 C fit in natural abundance 35 Cl 37 Cl Hotband *H. M. Pickett, J Mol Spec. 148 (1991) 371.

Fitting 13 C 111 -000 Transition

Results: Geometry Optimization *Hotband A=10692. 123(4) B=5090. 809(6) C=3434. 501(5) Reported in MHz

Anharmonic Ab Initio Results: CFE 35 Cl Experimental Results B 3 LYP 6 -31+g(3 d, 2 p) MP 2 6 -31+g(3 d, 2 p) A 10681. 648(2) 10637. 96441 10608. 90136 B 5102. 154(4) 5040. 89766 5074. 73661 C 3448. 308(3) 3420. 19752 3432. 70469 ΔJ 1. 2(2)E-03 1. 34406860 E-03 1. 312969 E-03 ΔJK 4. 5(4)E-03 5. 091317243 E-03 4. 905982 E-03 ΔK 4. 3(4)E-03 7. 026327603 E-03 7. 010683 E-03 δJ 4. 7(1)E-04 4. 495228752 E-04 4. 41918 E-04 δk 5. 6(6)E-03 5. 120794969 -03 4. 963329 E-03 Reported in MHz

Anharmonic Results: Vibrational Rotational Coupling Experimental Results (35 Cl) Experimental Results (Hotband) B 3 LYP 6 -31+g(3 d, 2 p) MP 2 6 -31+g(3 d, 2 p) A 10681. 648(2) 10692. 123(4) Ae 10638. 2055 10609. 14296 B 5102. 154(4) 5090. 809(6) Be 5041. 007467 5074. 845808 C 3448. 308(3) 3434. 501(5) Ce 3420. 277732 3432. 785356 A(0… 0) 10590. 66334 10560. 45257 B(0… 0) 5019. 655764 5052. 933481 C(0… 0) 3400. 94068 3413. 127519 αA -6. 993 α 4 A -10. 85060 -9. 79819 αB -0. 921 α 4 B -0. 49552 -0. 16486 αC 9. 205 α 4 C 1. 13954 1. 14290 Reported in MHz

Summary n Full 11 GHz Bandwidth (7. 5 -18. 5 GHz) q q q n Assignments q q n 10, 000 Averages Acquired in 40 Minutes 18, 000: 1 S/Nrms 4 Different Isotopic Species 1 Hotband Rotational Constants q Vibrational Rotational Coupling

Future Research n Additional Structures q q q n Deuterium Labeling Additional Hotbands Clusters Kritchman Analysis q q q Bond Length Bond Angles Structural Information

The Dian Group Professor q Dr. Brian C. Dian Post-Doc q Dr. Chandana Karunatilaka Graduate Students q Amanda Shirar q Giana Storck Undergraduates q Erin Biddle q Ricky Crawley Jr. Funding q Purdue University q Camille and Henry Dreyfus Young Faculty Award