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

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Presentation on theme: "MM-Wave Rotational Spectrum of Methyl Nitrate Jessica Thomas, Ivan Medvedev, Department of Physics, Wright State University David Dolson Department of."— Presentation transcript:

1 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

2 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 OUR INTEREST IN METHYL NITRATE http://commons.wikimedia.org/wiki/File:Methyl_nitrate_3D_ball.png

3 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 MeONO 2. THE SYNTHESIS Drying Setup Glass Wool CaCl 2 3-4mL MeONO 2 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

4 http://commons.wikimedia.org/wiki/File:Methyl_nitrate_3D_ball.png METHYL NITRATE, THE MOLECULE Molecular FormulaCH 3 NO 3 Molar Mass 77.04 g/mol Density1.203 g/cm 3 Melting point -82.3  C Dipole momentμ a = 3.1 D μ b =.25 D Colorless volatile liquid Ignited, it burns with a gray-blue flame Toxic when inhaled Difficult to store for extended periods of time

5 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 / MHz11795.06 B / MHz4707.52 C / MHz3438.29 I a / amu A 2 42.8596 I b / amu A 2 107.388 I c / amu A 2 147.030 I a + I b - I c 3.218 ҡ -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)

6 IF VDI Transmitter VDI Receiver Absorption Cell: length - 2 m, volume - 14 L x24 Stepping Synthesizer LO Sideband filter Computer IF detectorLock in Sweeping Synthesizer Gas Inlet Absorption Cell Custom Built Microwave Synthesizer Continuous Wave THz Spectrometer Microwave Synthesizer Custom Built Diode MultipliersVirginia Diodes Absorption Cell2 m long by 4in wide (14 L) OUR SYSTEM

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

8

9 Ground State 1 st Excited State

10 GROUND STATE 265 lines assigned with J numbers ranging from 24 to 38 ParameterCurrent Value a Previous Value A / MHz11795.12844(259) 11795.06 B / MHz4707.57017( 78) 4707.52 C / MHz3438.24379( 77) 3438.29 Δ J / kHz0.974760(295) Δ JK / kHz4.32862(109) Δ K / kHz4.4918(172) δ J / kHz0.249434(199) δ K / kHz2.7136( 43) Avg. / kHz.561 rms /kHz56.967

11 NUMERICS ParameterOld ValuesCurrent Value A / MHz11795.0611795.12844(259) B / MHz4707.524707.57017( 78)) C / MHz3438.293438.24379( 77) I a / amu A 2 42.8596 42.85930438 I b / amu A 2 107.388 107.386822 I c / amu A 2 147.030 147.0317496 I a + I b - I c 3.218 3.214376799 ҡ -0.696239 -0.696220199

12 1 ST EXCITED STATE

13 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

14 ParametersTentative Values A / MHz 11760.80302(277) B / MHz4704.80082(147) C / MHz3442.22668(130) AVG/ MHz-0.002452 RMS/MHz1.048496 1 ST EXCITED STATE Upper state: 29 7 22 Lower state: 28 7 21 A,q,R,29,0

15 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. Refine line lists Work towards the assignment of the excited state Extend assignment beyond 270 GHz Goals :


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