Chirped-Pulse millimeter-Wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions.

A Chirped-Pulse millimeter-Wave (CPmmW) spectrometer is applied to the study of chemical reaction products that result from pyrolysis in a Chen nozzle heated to 1000-1800 K. Millimeter-wave rotational spectroscopy unambiguously determines, for each polar reaction product, the species, the conformers, relative concentrations, conversion percentage from precursor to each product, and, in some cases, vibrational state population distributions. A chirped-pulse spectrometer can, within the frequency range of a single chirp, sample spectral regions of up to ∼10 GHz and simultaneously detect many reaction products. Here we introduce a modification to the CPmmW technique in which multiple chirps of different spectral content are applied to a molecular beam pulse that contains the pyrolysis reaction products. This technique allows for controlled allocation of its sensitivity to specific molecular transitions and effectively doubles the bandwidth of the spectrometer. As an example, the pyrolysis reaction of ethyl nitrite, CH3CH2ONO, is studied, and CH3CHO, H2CO, and HNO products are simultaneously observed and quantified, exploiting the multi-chirp CPmmW technique. Rotational and vibrational temperatures of some product molecules are determined. Subsequent to supersonic expansion from the heated nozzle, acetaldehyde molecules display a rotational temperature of 4 ± 1 K. Vibrational temperatures are found to be controlled by the collisional cooling in the expansion, and to be both species- and vibrational mode-dependent. Rotational transitions of vibrationally excited formaldehyde in levels ν4, 2ν4, 3ν4, ν2, ν3, and ν6 are observed and effective vibrational temperatures for modes 2, 3, 4, and 6 are determined and discussed.

[1]  Johanna Weiss,et al.  Laser And Coherence Spectroscopy , 2016 .

[2]  S. BtJTTERW.  Field in and , 2015 .

[3]  A. Suits,et al.  Isomer-specific mass spectrometric detection via "semisoft" strong-field ionization. , 2013, The journal of physical chemistry. A.

[4]  S. Leone,et al.  Isomer specific product detection in the reaction of CH with acrolein. , 2013, The journal of physical chemistry. A.

[5]  J. Daily,et al.  Pyrolysis of furan in a microreactor. , 2013, The Journal of chemical physics.

[6]  J. Daily,et al.  Biomass pyrolysis: thermal decomposition mechanisms of furfural and benzaldehyde. , 2013, The Journal of chemical physics.

[7]  D. Plusquellic,et al.  Segmented chirped-pulse Fourier transform submillimeter spectroscopy for broadband gas analysis. , 2013, Optics express.

[8]  S. Leone,et al.  Product branching fractions of the CH + propene reaction from synchrotron photoionization mass spectrometry. , 2013, The journal of physical chemistry. A.

[9]  J. Stanton,et al.  Calculation of fundamental frequencies for small polyatomic molecules: a comparison between correlation consistent and atomic natural orbital basis sets , 2013 .

[10]  Bryan M. Wong,et al.  A new approach toward transition state spectroscopy. , 2013, Faraday discussions.

[11]  J. Stanton,et al.  High-accuracy estimates for the vinylidene-acetylene isomerization energy and the ground state rotational constants of :C═CH2. , 2013, The journal of physical chemistry. A.

[12]  D. Patterson,et al.  Enantiomer-specific detection of chiral molecules via microwave spectroscopy , 2013, Nature.

[13]  Kirill Prozument,et al.  Chirped-pulse millimeter-wave spectroscopy: spectrum, dynamics, and manipulation of Rydberg-Rydberg transitions. , 2013, The Journal of chemical physics.

[14]  J. Daily,et al.  Thermal decomposition of CH3CHO studied by matrix infrared spectroscopy and photoionization mass spectroscopy. , 2012, The Journal of chemical physics.

[15]  B. Pate,et al.  An arbitrary waveform generator based chirped pulse Fourier transform spectrometer operating from 260 to 295 GHz , 2012 .

[16]  B. Pate,et al.  Broadband Molecular Rotational Spectroscopy Special Issue , 2012 .

[17]  T. Betz,et al.  Multi-resonance effects within a single chirp in broadband rotational spectroscopy: The rapid adiabatic passage regime for benzonitrile , 2012 .

[18]  Mason Inman.  Cooking up fuel , 2012 .

[19]  W. J. Lafferty,et al.  Microwave Spectra of Molecules of Astrophysical interest , 2012 .

[20]  Melanie Schnell,et al.  Broadband Rotational Spectroscopy for Molecular Structure and Dynamics Studies , 2012 .

[21]  Juan Wang,et al.  Absolute photoionization cross-sections of some combustion intermediates , 2012 .

[22]  Kirill Prozument,et al.  Chirped-pulse millimeter-wave spectroscopy of Rydberg-Rydberg transitions. , 2011, Physical review letters.

[23]  G. B. Park,et al.  Design and evaluation of a pulsed-jet chirped-pulse millimeter-wave spectrometer for the 70-102 GHz region. , 2011, The Journal of chemical physics.

[24]  Neil Savage,et al.  Fuel options: The ideal biofuel , 2011, Nature.

[25]  B. Pate,et al.  Next generation techniques in the high resolution spectroscopy of biologically relevant molecules. , 2011, Physical chemistry chemical physics : PCCP.

[26]  N. Savage.  The ideal biofuel , 2011 .

[27]  D. Obenchain,et al.  Rotational spectrum of three conformers of 3,3-difluoropentane: Construction of a 480 MHz bandwidth chirped-pulse Fourier-transform microwave spectrometer , 2010 .

[28]  J. Gauss,et al.  Quantum-chemical calculation of spectroscopic parameters for rotational spectroscopy , 2010 .

[29]  Calvin Mukarakate,et al.  Current technologies for analysis of biomass thermochemical processing: a review. , 2009, Analytica chimica acta.

[30]  J. Daily,et al.  Thermal decomposition of furan generates propargyl radicals. , 2009, The journal of physical chemistry. A.

[31]  D. Peterka,et al.  The multiplexed chemical kinetic photoionization mass spectrometer: a new approach to isomer-resolved chemical kinetics. , 2008, The Review of scientific instruments.

[32]  Gordon G. Brown,et al.  Conformational isomerization kinetics of pent-1-en-4-yne with 3,330 cm−1 of internal energy measured by dynamic rotational spectroscopy , 2008, Proceedings of the National Academy of Sciences.

[33]  Brooks H. Pate,et al.  Measuring Picosecond Isomerization Kinetics via Broadband Microwave Spectroscopy , 2008, Science.

[34]  Gordon G. Brown,et al.  A broadband Fourier transform microwave spectrometer based on chirped pulse excitation. , 2008, The Review of scientific instruments.

[35]  Bin Yang,et al.  Near-threshold absolute photoionization cross-sections of some reaction intermediates in combustion , 2008 .

[36]  C. Moore.  A spectroscopist's view of energy states, energy transfers, and chemical reactions. , 2007, Annual review of physical chemistry.

[37]  Henry J. Curran,et al.  Rate constant estimation for C1 to C4 alkyl and alkoxyl radical decomposition , 2006 .

[38]  David M. Smith.  Vibration-rotation interactions between overtone and combination levels of asymmetric-top molecules: application to the infrared spectroscopy of formaldehyde and ketene. , 2005, The Journal of chemical physics.

[39]  Lionel Poisson,et al.  Selective detection of isomers with photoionization mass spectrometry for studies of hydrocarbon flame chemistry , 2003 .

[40]  J. T. Mckinnon,et al.  Intense, hyperthermal source of organic radicals for matrix-isolation spectroscopy , 2003 .

[41]  J. M. Merritt,et al.  Free radicals in superfluid liquid helium nanodroplets: A pyrolysis source for the production of propargyl radical , 2002, physics/0608086.

[42]  W. O. George,et al.  Ab initio computations on simple carbonyl compounds , 2000 .

[43]  Igor I. Leonov,et al.  A portable, pulsed-molecular-beam, Fourier-transform microwave spectrometer designed for chemical analysis , 1999 .

[44]  F. D. Lucia,et al.  Millimeterwave spectroscopy of active laser plasmas; the excited vibrational states of HCN , 1999 .

[45]  P. Davies,et al.  Pulse pyrolysis infrared laser jet spectroscopy of free radicals , 1998 .

[46]  H. Padmore,et al.  Performance of the vacuum ultraviolet high-resolution and high-flux beamline for chemical dynamics studies at the Advanced Light Source , 1997 .

[47]  F. Lovas,et al.  Microwave spectra of molecules of astrophysical interest: XXIII : Acetaldehyde , 1996 .

[48]  Gisbert Winnewisser,et al.  The Ground State Rotational Spectrum of Formaldehyde , 1996 .

[49]  J. Leszczynski,et al.  Acetaldehyde: Harmonic Frequencies, Force Field, and Infrared Intensities. , 1996 .

[50]  William F. Polik,et al.  Pure vibrational spectroscopy of S0 formaldehyde by dispersed fluorescence , 1996 .

[51]  S. Kable,et al.  A new design for a simple and effective pyrolysis nozzle in a supersonic free jet , 1996 .

[52]  Kenneth L. Ratzlaff,et al.  A COMPACT HOT-NOZZLE FOURIER-TRANSFORM MICROWAVE SPECTROMETER , 1995 .

[53]  B. Argrow,et al.  Fourier transform infrared absorption spectroscopy of jet‐cooled radicals , 1995 .

[54]  Fumiaki Ito.  FTIR spectra of the 2?4, ?4 + ?6 and 2?6 bands of formaldehyde , 1994 .

[55]  Ian W. M. Smith,et al.  Ultralow temperature kinetics of neutral–neutral reactions. The technique and results for the reactions CN+O2 down to 13 K and CN+NH3 down to 25 K , 1994 .

[56]  G. A. Bethardy,et al.  The role of molecular flexibility in accelerating intramolecular vibrational relaxation , 1994 .

[57]  D. Kohn,et al.  Flash pyrolysis nozzle for generation of radicals in a supersonic jet expansion , 1992 .

[58]  N. Karlov,et al.  Intense resonant interactions in quantum electronics , 1991 .

[59]  M. Harmony,et al.  Laser-excitation spectrum and structure of CCl2 in a free-jet expansion from a heated nozzle , 1989 .

[60]  M. Head‐Gordon,et al.  A fifth-order perturbation comparison of electron correlation theories , 1989 .

[61]  H. S. Gutowsky,et al.  The silicon-carbon double bond: theory takes a round , 1989 .

[62]  D. Clouthier,et al.  Pyrolysis jet spectroscopy , 1988 .

[63]  Peter R. Taylor,et al.  General contraction of Gaussian basis sets. I. Atomic natural orbitals for first‐ and second‐row atoms , 1987 .

[64]  André Fayt,et al.  Global Rovibrational Analysis of Carbonyl Sulfide , 1986 .

[65]  S. Colson,et al.  Flash pyrolytic production of rotationally cold free radicals in a supersonic jet. Resonant multiphoton spectrum of the 3p2A2" .rarw. X2A2" origin band of methyl , 1986 .

[66]  J. B. Pedley,et al.  Thermochemical data of organic compounds , 1986 .

[67]  H. Müller,et al.  Submillimeter, millimeter, and microwave spectral line catalog. , 1985, Applied optics.

[68]  J. L. Kinsey,et al.  Rotation‐induced vibrational mixing in X̃ 1A1 formaldehyde: Non−negligible dynamical consequences of rotation , 1985 .

[69]  J. Muenter,et al.  Vibrational relaxation of linear molecules in a nozzle expansion , 1984 .

[70]  Hajime Ito,et al.  Millimeter wave spectroscopy of OCS in vibrationally excited states , 1984 .

[71]  N. J. Smith,et al.  Studies of vibrational relaxation in OCS and CF4 by pulsed photoacoustic techniques , 1984 .

[72]  J. Kestin,et al.  Equilibrium and transport properties of the noble gases and their mixtures at low density , 1984 .

[73]  N. Westwood,et al.  The microwave spectrum of an unstable molecule: Chloroketene ClHCCO , 1983 .

[74]  G. Flynn.  Collision-induced energy flow between vibrational modes of small polyatomic molecules , 1981 .

[75]  W. Flygare,et al.  Fabry–Perot cavity pulsed Fourier transform microwave spectrometer with a pulsed nozzle particle source , 1981 .

[76]  M. L. Mandich,et al.  Collisional relaxation of vibrationally excited OCS in rare gas mixtures , 1980 .

[77]  M. L. Mandich,et al.  Vibrational energy transfer map for OCS , 1980 .

[78]  D. Dangoisse,et al.  Microwave spectra of molecules of astrophysical interest. XVIII. Formic acid , 1980 .

[79]  L. Batt.  The gas‐phase decomposition of alkoxy radicals , 1979 .

[80]  Michael J. Corkill,et al.  Microwave spectra and structures of cis- and trans-methyl nitrite. Methyl barrier in trans-methyl nitrite , 1979 .

[81]  G. McClelland,et al.  Vibrational and rotational relaxation of iodine in seeded supersonic beams , 1979 .

[82]  G. Flynn,et al.  Translational and vibrational energy distributions in metastable laser pumped polyatomic molecules: A quasithermodynamic description , 1978 .

[83]  R. Mariella,et al.  Vibrational relaxation in seeded supersonic alkali halide beams , 1977 .

[84]  L. Batt,et al.  The gas‐phase pyrolysis of alkyl nitrites. IV. Ethyl nitrite , 1976 .

[85]  L. Batt,et al.  Heats of formation of C1C4 alkyl nitrites (RONO) and their RO‐NO bond dissociation energies , 1974 .

[86]  T. Schmalz,et al.  Fast passage in rotational spectroscopy: Theory and experiment , 1974 .

[87]  W. Flygare,et al.  Transient absorption and emission and the measurement of T1 and T2 in the J O→1 rotational transition in OCS , 1974 .

[88]  Barbara M. Hopkins,et al.  Vibrational relaxation of OCS in HBr, HCl, and rare gaseous mixtures , 1973 .

[89]  S. Saito,et al.  Microwave spectrum of nitroxyl , 1973 .

[90]  T. Oka,et al.  Microwave spectrum of formaldehyde in vibrationally excited states , 1964 .

[91]  J. Levy.  The Thermal Decomposition of Ethyl Nitrite1,2 , 1956 .

[92]  F. H. Pollard,et al.  The thermal decomposition of ethyl nitrate , 1956 .