MMWave Rotational Spectrum of Methyl Nitrate Jessica Thomas

MM-Wave Rotational Spectrum of Methyl Nitrate Jessica Thomas, Ivan Medvedev, Department of Physics, Wright State University David Dolson Department of Chemistry, Wright State University

OUR INTEREST IN METHYL NITRATE • Chemical related to metabolism • With diabetes this chemical has been known to be on the order of parts per trillion. • Also, it is known to be expressed in breath in children with type 1 diabetes. • Likely, oxidative stress on individuals during hyperglycemia in type 1 diabetics causes methyl nitrate production. • Could be an indicator used for air quality monitoring • Possesses explosive qualities • Could be a molecule of interest in interstellar medium http: //commons. wikimedia. org/wiki/File: Methyl_nitrate_3 D_ball. png

THE SYNTHESIS The synthesis of this chemical was done by scaling down and following the procedures published in Organic Syntheses. Our experiment was done to yield roughly 3 -4 ml of Me. ONO 2. Glass Wool • Nitration of methanol by a mixture of sulfuric and nitric acid. • Sulfuric acid is used as a catalyst and an absorber of water • The product was dried to remove any excess water Ca. Cl 2 3 -4 m. L Me. ONO 2 Drying Setup

METHYL NITRATE, THE MOLECULE • Colorless volatile liquid Molecular Formula CH 3 NO 3 77. 04 g/mol Molar Mass • Ignited, it burns with a gray -blue flame Density 1. 203 g/cm 3 Melting point -82. 3 C • Toxic when inhaled Dipole moment μa = 3. 1 D μb =. 25 D • Difficult to store for extended periods of time http: //commons. wikimedia. org/wiki/File: Methyl_nitrate_3 D_ball. png

PREVIOUS RESEARCH Dixon, W. , & Wilson JR, E. B. (1961, July 1). Microwave Spectrum of Methyl Nitrate. The Journal of Chemical Physics, 35, 191 -198. Parameter A / MHz B / MHz C / MHz Ia / amu A 2 Ib/ amu A 2 Ic/ amu A 2 Ia+ Ib- Ic ҡ 11795. 06 4707. 52 3438. 29 42. 8596 107. 388 147. 030 3. 218 -0. 696239 This paper also discusses briefly the excited state of methyl nitrate. SUBMILLIMETER ROTATIONAL SPECTRA OF METHYL NITRATE, Drouin, Brian J. ; Zhang, Xu; Ellison, G. Barney, 2008, Columbus (400 -440 GHz)

Gas Inlet OUR SYSTEM Continuous Wave THz Spectrometer Diode Multipliers Virginia Diodes Absorption Cell 2 m long by 4 in wide (14 L) x 24 Lock in IF detector Computer LO Sideband filter Stepping Synthesizer Sweeping Synthesizer Custom Built Microwave Synthesizer IF VDI Receiver Custom Built VDI Transmitter Microwave Synthesizer Absorption Cell: length - 2 m , volume - 14 L Absorption Cell

THE SPECTRUM • prolate asymmetric top with the moments of inertia along the three principle axes falling into the order Ia Ib Ic. • For asymmetric tops the allowed transitions all obey selection rules ∆J = 0, ± 1 and the components of dipole moments dictate the transitions between Ka and Kc. • a-type transition has the selection rules ∆ Ka = 0(± 2, ± 4) and ∆ Kc = ± 1(± 3, ± 5) B C • b-type transition has the selection rules ∆ Ka = 1(± 3, . . . ) and ∆ Kc = ± 1(± 3, …) A

Ground State 1 st Excited State

GROUND STATE 265 lines assigned with J numbers ranging from 24 to 38 Parameter Current Valuea Previous Value 11795. 06 A / MHz 11795. 12844(259) 4707. 52 B / MHz 4707. 57017( 78) 3438. 29 C / MHz 3438. 24379( 77) ΔJ / k. Hz 0. 974760(295) ΔJK / k. Hz 4. 32862(109) ΔK / k. Hz 4. 4918(172) δJ / k. Hz 0. 249434(199) δK / k. Hz 2. 7136( 43) Avg. / k. Hz. 561 rms /k. Hz 56. 967

NUMERICS Parameter Old Values Current Value A / MHz 11795. 06 11795. 12844(259) B / MHz 4707. 52 4707. 57017( 78)) C / MHz 3438. 29 3438. 24379( 77) Ia / amu A 2 42. 8596 42. 85930438 Ib/ amu A 2 107. 388 107. 386822 Ic/ amu A 2 147. 030 147. 0317496 Ia+ Ib- Ic 3. 218 3. 214376799 ҡ -0. 696239 -0. 696220199

1 ST EXCITED STATE

1 ST EXCITED STATE Perturbed lines from likely a combination of the v=1 methyl torsion and the v=1 NO 2 torsion. Upper state: 30 6 25 Lower state: 29 6 24 a, q, R, 30, -1 Upper state: 31 5 27 Lower state: 30 5 26 a, q, R, 31, -1 Upper state: 28 8 20 Lower state: 27 8 19 a, q, R, 28, 0 Upper state: 31 4 27 Lower state: 30 4 26 a, q, R, 31, 0

1 ST EXCITED STATE Parameters Tentative Values A / MHz 11760. 80302(277) B / MHz 4704. 80082(147) C / MHz 3442. 22668(130) AVG/ MHz -0. 002452 RMS/MHz 1. 048496 Upper state: 29 7 22 Lower state: 28 7 21 A, q, R, 29, 0

CONCLUSION AND STEPS FORWARD This experiment assigned the ground state and offered a rough estimate of the assignment of first vibrational state between 210 -270. By doin so we were able to refined the rotational constants that were furnished by previous the microwave study of this molecule. Goals: • Refine lists • Work towards the assignment of the excited state • Extend assignment beyond 270 GHz