Waveguide Chirped-Pulse Fourier Transform Microwave

Spectroscopy of 2-Ethoxyethanol

Maria A. Phillips, Steven Shipman

New College of Florida

Background• Methoxymethanol: predicted

to be in the ISM – Hays et al.

• 2-Methoxyethanol: Caminati

et al.

• 2-Ethoxyethanol: Slightly

larger, no previous MW Work

Hays B. M.; Widicus Weaver S. L. J. Phys. Chem. A, in press 2013Caminati, W.; Meyer, R.; Smith, Z. Chemical Physics, 1986, 110, 67-82

Computational Chemistry

Debye

|μa| 2.033

|μb| 1.5781

|μc| 0.083

gg’tt 0 cm-

1

gg’tg 440 cm-1

gg’tg’ 530 cm-1

gg’g’t 630 cm-1

El-Hefnawy, M.; Sameshima, K.; Matsushita, T.; Tanaka, R.; Chemical Society of Japan, 2006, 79, 845 – 856Tafazzoli, M.; Jalil, S.; Theoretical Chemistry Accounts, 2002, 107, 162 – 172

Experimental Set Up

• 8.7 – 13.5 GHz

• 13.5 – 18.3 GHz

• 18.0 – 26.5 GHz

2-Ethoxyethanol

1M shots-20 oC7 mTorr4 μs FID

Triples Fitter• Predict spectrum from an initial guess• Select three transitions expected to be present (used for fitting)• Select another 10 – 20 transitions also expected to be present

(used for scoring)• Assign experimental peaks to fitting transitions, run SPFIT then

SPCAT and score the resulting spectrum• Repeat for many combinations of experimental peaks and rank

the results

EEO GS CalculatedB3LYP/6-311+

+G(d,p)

Triples Fitter Current

A (MHz) 8761.148 8701.3 8795.65(41)

B (MHz) 1612.882 1631.52 1630.98(75)

C (MHz) 1457.318 1472.37 1473.45(70)

ΔJ (kHz) 0.5174 0.5174 0.496318(187)

ΔJK (kHz) -4.700 -4.700 -4.45233(141)

ΔK (kHz) 459.77 459.77 434.271( 88)

δJ (kHz) 0.114 0.1140.1057660(15

6)δK (kHz) 3.314 3.314 3.16146( 78)

ΦJ(Hz) -- ---0.7612(82)E-

03ΦKJ(Hz) -- -- -0.07091(133)

φJ(Hz) -- --0.17192(167)E

-03Fit RMS (kHz)

-- -- 57

Highest J -- -- 113

Lines Fit -- -- 330

2-Ethoxyethanol

Future Work

Future Work

EEO ES Current

A (MHz) 8759.7828(78)

B (MHz)1625.16201(15

9)

C (MHz)1473.57295(14

8)ΔJ (kHz) 0.3724( 47)

ΔJK (kHz) 11.460( 57)

ΔK (kHz) 73.427(124)

δJ (kHz) 0.24220( 48)

δK (kHz) 5.008( 89)

Fit RMS (kHz) 94

Highest J 29

Lines Fit 109

Excited State Fit: Possible Ethyl Torsion

Acknowledgements

Dr. Steven Shipman

Bri Gordon

Benjamin Rooks

Christian Metzger

Ian Finneran

Benjamin Reinhold

Erin Kent

Morgan McCabe

New College of Florida

National Science Foundation

Office of Naval Research

Expanded View

Flow – Through Chiller System