Leonid Sheps

Principal Member of Technical Staff

Author profile picture

Principal Member of Technical Staff

lsheps@sandia.gov

Biography

Leonid (Lenny) Sheps is a Principal Member of the Technical Staff at Sandia National Laboratory. Throughout his academic and post-doc research career, he has studied the use of femtosecond laser pulses to study chemical reactions and vibrational energy transfer in liquids, and later focused on excited–state solvation and charge transfer in molecular clusters. His current research at Sandia focuses on gas-phase chemical reactions and on the dynamics of energy and charge transfer in gas-phase molecules and clusters. To unravel competing chemical pathways in complex reaction networks, such as hydrocarbon oxidation, we develop and use laser photolysis and flow reactors that operate at gas pressures up to 100 bar and temperatures up to 1000 K. We monitor the chemical composition of reacting mixtures with microsecond to millisecond-time resolution using unique home-built tools, including a highly sensitive photoionization mass spectrometer, an ultra-broadband UV-VIS cavity-enhanced absorption spectrometer, and a Fluorescence Assay by Gas Expansion (FAGE) apparatus. These experiments characterize and quantify key reaction intermediates (e.g., free radicals and thermally unstable closed-shell species) on par with long-lived reaction products, providing detailed probing of complex chemical mechanisms. We compare the experimental results with computations from colleagues at Sandia, Argonne National Laboratory, and other institutions.

We are also studying the excited-state dynamics of electron donor-acceptor systems, such as push-pull molecules and organic molecule-rare gas clusters. The target molecules and clusters will be entrained in supersonic beams and excited with UV laser pulses. The subsequent dynamics of charge transfer, coupled to electronic and vibrational energy transfer, isomerization, and dissociation will be investigated on femtosecond- to nanosecond timescales via time-resolved photoelectron spectroscopy with velocity-map ion and electron imaging.

Research Interests: Chemical kinetics and dynamics, photochemistry, and molecular spectroscopy. Google Scholar

Education

Ph.D.Physical ChemistryUniversity of Wisconsin-Madison2005
B.S.Biology and ChemistryNorthland College, Wisconsin1998

Publications

  • Cho, J., Rosch, D., Tao, Y., Osborn, D.L., Klippenstein, S.J., Sheps, L., Sivaramakrishnan, R., & Sivaramakrishnan, R. (2023). Modeling–Experiment–Theory Analysis of Reactions Initiated from Cl + Methyl Formate. Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, 127(46), pp. 9804-9819. https://doi.org/10.1021/acs.jpca.3c05085 Publication ID: 122920
  • Zou, M., Liu, T., Vansco, M.F., Sojdak, C.A., Markus, C.R., Almeida, R., Au, K., Sheps, L., Osborn, D.L., Winiberg, F.A.F., Percival, C.J., Taatjes, C.A., Klippenstein, S.J., Lester, M.I., Caravan, R.L., & Caravan, R.L. (2023). Bimolecular Reaction of Methyl-Ethyl-Substituted Criegee Intermediate with SO2. Journal of Physical Chemistry A, 127(43), pp. 8994-9002. https://doi.org/10.1021/acs.jpca.3c04648 Publication ID: 122992
  • Demireva, M., Sheps, L., Hansen, N., & Hansen, N. (2023). Insights into Constraining Rate Coefficients in Fuel Oxidation Mechanisms Using Genetic Algorithm Optimization. Energy and Fuels, 37(18), pp. 14240-14253. https://doi.org/10.1021/acs.energyfuels.3c02129 Publication ID: 123088
  • Liu, T., Elliott, S.N., Zou, M., Vansco, M.F., Sojdak, C.A., Markus, C.R., Almeida, R., Au, K., Sheps, L., Osborn, D.L., Percival, C.J., Taatjes, C.A., Caravan, R.L., Klippenstein, S.J., Lester, M.I., & Lester, M.I. (2023). OH Roaming and Beyond in the Unimolecular Decay of the Methyl-Ethyl-Substituted Criegee Intermediate: Observations and Predictions. Journal of the American Chemical Society, 145(35), pp. 19405-19420. https://doi.org/10.1021/jacs.3c07126 Publication ID: 123220
  • Choudhary, H., Das, L., Pelton, J.G., Sheps, L., Simmons, B.A., Gladden, J.M., Singh, S., & Singh, S. (2023). Funneled Depolymerization of Ionic Liquid-Based Biorefinery “Heterogeneous” Lignin into Guaiacols over Reusable Palladium Catalyst. Chemistry – A European Journal, 29(27). https://doi.org/10.1002/chem.202300330 Publication ID: 123672
  • Johansen, S.L., Sheps, L., Zador, J., Au, K., & Au, K. (2022). Investigating Methylamine Oxidation with Computational Chemistry and Photoionization Mass Spectrometry: Insight into the Reactivity of C-centered and N-centered Radicals [Conference Presenation]. https://doi.org/10.2172/2006327 Publication ID: 121996
  • Couch, D.E., Mulvihill, C., Taatjes, C.A., Sheps, L., & Sheps, L. (2022). Time-resolved quantification of ROO, OOQOOH, KHP in dimethyl ether oxidation [Conference Presenation]. https://doi.org/10.2172/2004337 Publication ID: 116564
  • Demireva, M., Oreluk, J., Dewyer, A.L., Zador, J., Sheps, L., & Sheps, L. (2022). Genetic Algorithm Optimization of A Theory-Based Low-Temperature Cyclopentane Oxidation Model [Conference Presenation]. https://doi.org/10.2172/2004466 Publication ID: 117052
  • Johansen, S.L., Sheps, L., Zador, J., Au, K., Eskola, A., & Eskola, A. (2022). Investigating Amine Oxidation with Computational Chemistry and Photoionization Mass Spectrometry: Insight into the Reactivity of C-centered and N-centered Radicals [Conference Presenation]. https://doi.org/10.2172/2004476 Publication ID: 117092
  • Sheps, L., Zador, J., Johansen, S.L., & Johansen, S.L. (2022). Investigating Structure and Reactivity Relationships of Nitrogen-Containing Radicals with Computational Chemistry and Photoionization Mass Spectrometry [Conference Presenation]. https://doi.org/10.2172/2003727 Publication ID: 114200
  • Sheps, L. (2022). Quantitative Probing of Autoignition Intermediates at High Pressures by Time-Resolved VUV Photoionization Mass Spectrometry [Conference Presenation]. https://doi.org/10.2172/2003710 Publication ID: 114132
  • Hansen, N., Taatjes, C.A., Zador, J., Chen, J., Najm, H.N., Sheps, L., Osborn, D.L., Ramasesha, K., & Ramasesha, K. (2022). Chemical Kinetics at SNL [Conference Presenation]. https://doi.org/10.2172/2003528 Publication ID: 113428
  • Demireva, M., Oreluk, J., Dewyer, A.L., Zador, J., Sheps, L., & Sheps, L. (2022). A Low Temperature Cyclopentane Oxidation Kinetics Model: Optimization of A Theory Based Sub Mechanism Against Experiment [Conference Presenation]. https://doi.org/10.2172/2003476 Publication ID: 113228
  • Oreluk, J., Sheps, L., Najm, H.N., & Najm, H.N. (2022). Bayesian Optimal Experimental Design for Photoionization Mass Spectrometry Experiments [Conference Presenation]. https://doi.org/10.2172/2003048 Publication ID: 111648
  • Oreluk, J., Sheps, L., Najm, H.N., & Najm, H.N. (2022). Exploring Bayesian Optimal Experimental Designs for High-dimensional Combustion Systems [Conference Presenation]. https://doi.org/10.2172/2002385 Publication ID: 110472
  • Rotavera, B., Huang, H., Antonov, I.O., Sheps, L., Zador, J., Taatjes, C.A., & Taatjes, C.A. (2022). Analysis of OH and HO2 Time Histories Measured in Low-Temperature Oxidation of Hexene Isomers [Conference Poster]. https://www.osti.gov/biblio/2002369 Publication ID: 110416
  • Buras, Z., Hansen, N., Taatjes, C.A., Sheps, L., & Sheps, L. (2022). Prospects and Limitations of Predicting Fuel Ignition Properties from Low-Temperature Speciation Data. Energy and Fuels, 36(6), pp. 3229-3238. https://doi.org/10.1021/acs.energyfuels.1c03342 Publication ID: 80510
  • Ramasesha, K., Tross, J., Schrader, P., Sheps, L., Au, K., & Au, K. (2021). Table-Top High Photon Energy Sources for Chemical Dynamics Investigations. https://doi.org/10.2172/1820243 Publication ID: 75650
  • Sheps, L., Osborn, D.L., Hansen, N., & Hansen, N. (2021). A New Approach to Fundamental Mechanism Discovery in Polymer Upcycling. https://doi.org/10.2172/1821555 Publication ID: 75826
  • Sheps, L., Dewyer, A.L., Demireva, M., Zador, J., & Zador, J. (2021). Quantitative Detection of Products and Radical Intermediates in Low-Temperature Oxidation of Cyclopentane. Journal of Physical Chemistry A, 125(20), pp. 4467-4479. https://doi.org/10.1021/acs.jpca.1c02001 Publication ID: 78245
  • Oreluk, J., Sheps, L., Najm, H.N., & Najm, H.N. (2021). Bayesian Optimal Experimental Design for Chemical Rate Constant Measurement using Mass Spectrometry [Conference Presenation]. https://doi.org/10.2172/1855329 Publication ID: 77548
  • Christianson, M.G., Doner, A.C., Davis, M.M., Koritzke, A.L., Turney, J.M., Schaefer, H.F., Sheps, L., Osborn, D.L., Taatjes, C.A., Rotavera, B., & Rotavera, B. (2021). Reaction mechanisms of a cyclic ether intermediate: Ethyloxirane. International Journal of Chemical Kinetics, 53(1), pp. 43-59. https://doi.org/10.1002/kin.21423 Publication ID: 74848
  • Couch, D.E., Au, K., Taatjes, C.A., Sheps, L., & Sheps, L. (2020). Quantification of Intermediates in Dimethyl Ether Oxidation [Conference Poster]. https://doi.org/10.2172/1837738 Publication ID: 72379
  • Hansen, N., Kukkadapu, G., Chen, B., Dong, S., Curran, H., Taatjes, C.A., Eskola, A., Osborn, D., Sheps, L., Pitz, W., Moshammer, K., Jasper, A., Chen, W., Yang, J., Z, W., & Z, W. (2020). The impact of the third O2 addition reaction network on ignition delay times of neo-pentane [Conference Presenation]. https://doi.org/10.2172/1837149 Publication ID: 72319
  • Sheps, L., Au, K., Demireva, M., & Demireva, M. (2020). Direct time-resolved detection and quantification of key reactive intermediates in diethyl ether oxidation at: T = 450-600 K. Physical Chemistry Chemical Physics, 22(42), pp. 24649-24661. https://doi.org/10.1039/d0cp03861j Publication ID: 71392
  • Doner, A.C., Davis, M.M., Koritzke, A.L., Christianson, M.G., Turney, J.M., Schaefer, H.F., Sheps, L., Osborn, D.L., Taatjes, C.A., Rotavera, B., & Rotavera, B. (2020). Isomer-Dependent Reaction Mechanisms of Cyclic Ether Intermediates: cis-23-Dimethyloxirane and trans-23-Dimethyloxirane. International Journal of Chemical Kinetics, 53(1), pp. 127-145. https://doi.org/10.1002/kin.21429 Publication ID: 100196
  • Sheps, L., Buras, Z., Zador, J., Au, K., Safta, C., & Safta, C. (2020). Rapid Assessment of Autoignition Propensity in Novel Fuels and Blends. https://doi.org/10.2172/1671001 Publication ID: 100148
  • Buras, Z., Hansen, N., Lopez-Pintor, D., Sheps, L., Taatjes, C.A., & Taatjes, C.A. (2020). Correlating Ignition Properties with Critical Species Concentrations [Conference Poster]. https://www.osti.gov/biblio/1813284 Publication ID: 74473
  • Buras, Z., Safta, C., Zador, J., Sheps, L., & Sheps, L. (2020). Simulated production of OH, HO2, CH2O, and CO2 during dilute fuel oxidation can predict 1st-stage ignition delays. Combustion and Flame, 216, pp. 472-484. https://doi.org/10.1016/j.combustflame.2019.12.013 Publication ID: 64964
  • Osborn, D.L., Eskola, A., Sheps, L., Taatjes, C.A., & Taatjes, C.A. (2020). Towards Understanding Autoignition Chemistry of Fuel-Air(Oxygen) Mixtures Important for New IC-Engine Technologies Using a Novel High-Pressure Reactor Interfaced with a Synchrotron Photoionization Time-of-Flight Mass-Spectrometer [Conference Poster]. https://www.osti.gov/biblio/1762579 Publication ID: 70819
  • Sheps, L., Antonov, I., Au, K., & Au, K. (2019). Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures. Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, 123(50), pp. 10804-10814. https://doi.org/10.1021/acs.jpca.9b08393 Publication ID: 64640
  • Antonov, I., Voronova, K., Chen, M.W., Sztaray, B., Hemberger, P., Bodi, A., Osborn, D.L., Sheps, L., & Sheps, L. (2019). To Boldly Look Where No One Has Looked Before: Identifying the Primary Photoproducts of Acetylacetone. Journal of Physical Chemistry A, 123(26), pp. 5472-5490. https://doi.org/10.1021/acs.jpca.9b04640 Publication ID: 67785
  • Osborn, D.L., Sheps, L., Sztaray, B., Antonov, I., Voronova, K., Bodi, A., Hemberger, P., & Hemberger, P. (2019). Photodissociation of Acetylacetone: Photoionization and Threshold Photoelectron Spectroscopy Reveal Much More Than OH Radicals [Conference Poster]. https://www.osti.gov/biblio/1582126 Publication ID: 64166
  • Caravan, R.L., Khan, M.A.H., Zador, J., Sheps, L., Antonov, I.O., Rotavera, B., Ramasesha, K., Au, K., Chen, M.W., Roesch, D., Osborn, D.L., Fittschen, C., Schoemaecker, C., Duncianu, M., Grira, A., Dusanter, S., Tomas, A., Percival, C.J., Shallcross, D.E., Taatjes, C.A., & Taatjes, C.A. (2018). The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. Nature Communications, 9(1). https://doi.org/10.1038/s41467-018-06716-x Publication ID: 59520
  • Buras, Z., Au, K., Safta, C., Zador, J., Sheps, L., & Sheps, L. (2018). Coupling FAGE Detection of OH and HO2 with a High-Pressure Reactor for Biofuel Characterization [Conference Poster]. https://www.osti.gov/biblio/1574564 Publication ID: 60159
  • Buras, Z., Safta, C., Zador, J., Sheps, L., & Sheps, L. (2018). Using OH and HO2 Radicals as Markers of Biofuel Ignition Properties [Conference Poster]. https://www.osti.gov/biblio/1571559 Publication ID: 63220
  • Sheps, L. (2018). Catching Molecules in the Act: what can we learn from direct probing of short-lived reaction intermediates? [Presentation]. https://www.osti.gov/biblio/1505262 Publication ID: 61375
  • Stone, D., Au, K., Sime, S., Medeiros, D.J., Blitz, M., Seakins, P.W., Decker, Z., Sheps, L., & Sheps, L. (2018). Unimolecular decomposition kinetics of the stabilised Criegee intermediates CH2OO and CD2OO. Physical Chemistry Chemical Physics, 20(38), pp. 24940-24954. https://doi.org/10.1039/c8cp05332d Publication ID: 63360
  • Caravan, R.L., Eskola, A.J., Antonov, I.O., Winiberg, F.A.F., Rotavera, B., Ramasesha, K., Sheps, L., Osborn, D.L., Percival, C.J., Shallcross, D.E., Taatjes, C.A., & Taatjes, C.A. (2018). Formation of low-volatility products in reactions of carbonyl oxide criegee intermediates [Conference Poster]. 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85105674576&origin=inward Publication ID: 63242
  • Bannan, T.J., Murray Booth, A., le Breton, M., Bacak, A., Muller, J.B.A., Leather, K.E., Khan, M.A.H., Lee, J.D., Dunmore, R.E., Hopkins, J.R., Fleming, Z.L., Sheps, L., Taatjes, C.A., Shallcross, D.E., Percival, C.J., & Percival, C.J. (2017). Seasonality of Formic Acid (HCOOH) in London during the ClearfLo Campaign: Seasonality of Formic Acid in London. Journal of Geophysical Research: Atmospheres, 122(22), pp. 1-12. https://doi.org/10.1002/2017JD027064 Publication ID: 54582
  • Assaf, E., Sheps, L., Whalley, L., Heard, D., Tomas, A., Schoemaecker, C., Fittschen, C., & Fittschen, C. (2017). The Reaction between CH3O2 and OH Radicals: Product Yields and Atmospheric Implications. Environmental Science and Technology, 51(4), pp. 2170-2177. https://doi.org/10.1021/acs.est.6b06265 Publication ID: 53471
  • Antonov, I.O., Chen, M., Voronova, K., Sztaray, B., Sheps, L., Osborn, D.L., & Osborn, D.L. (2017). Photodissociation dynamics of acetylacetone [Conference Poster]. https://www.osti.gov/biblio/1418227 Publication ID: 52936
  • Sheps, L., Rotavera, B., Eskola, A.J., Osborn, D.L., Taatjes, C.A., Au, K., Shallcross, D.E., Khan, M.A.H., Percival, C.J., & Percival, C.J. (2017). The reaction of Criegee intermediate CH2OO with water dimer: Primary products and atmospheric impact. Physical Chemistry Chemical Physics, 19(33), pp. 21970-21979. https://doi.org/10.1039/c7cp03265j Publication ID: 57797
  • Decker, Z.C.J., Au, K., Vereecken, L., Sheps, L., & Sheps, L. (2017). Direct experimental probing and theoretical analysis of the reaction between the simplest Criegee intermediate CH2OO and isoprene. Physical Chemistry Chemical Physics, 19(12), pp. 8541-8551. https://doi.org/10.1039/c6cp08602k Publication ID: 55224
  • Eskola, A.J., Antonov, I.O., Sheps, L., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2017). Time-resolved measurements of product formation in the low-temperature (550-675 K) oxidation of neopentane: A probe to investigate chain-branching mechanism [Conference Poster]. Physical Chemistry Chemical Physics. https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85022088258&origin=inward Publication ID: 43582
  • Scheer, A.M., Eskola, A.J., Osborn, D.L., Sheps, L., Taatjes, C.A., & Taatjes, C.A. (2016). Resonance stabilization effects on ketone autoxidation: Isomer-Specific cyclic ether and ketohydroperoxide formation in the low-Temperature (400−625 k) oxidation of diethyl ketone. Journal of Physical Chemistry A, 120(43), pp. 8625-8636. https://doi.org/10.1021/acs.jpca.6b07370 Publication ID: 55463
  • Sheps, L. (2016). Measurements of Key Chemical Intermediates in Low-T combustion [Conference Poster]. https://www.osti.gov/biblio/1405226 Publication ID: 47278
  • Osborn, D.L., Taatjes, C.A., Zador, J., Savee, J.D., Sheps, L., Welz, O., & Welz, O. (2016). Kinetics and Spectroscopy of a QOOH Reactive Intermediate [Conference Poster]. https://www.osti.gov/biblio/1404766 Publication ID: 47032
  • Antonov, I.O., Zador, J., Rotavera, B., Papajak, E., Osborn, D.L., Taatjes, C.A., Sheps, L., & Sheps, L. (2016). Pressure-dependent competition among reaction pathways from first- and second-O2 additions in the low-temperature oxidation of tetrahydrofuran. Journal of Physical Chemistry A, 120(33), pp. 6582-6595. https://doi.org/10.1021/acs.jpca.6b05411 Publication ID: 51050
  • Rotavera, B., Antonov, I.O., Caravan, R.L., Zador, J., Sheps, L., Taatjes, C.A., Osborn, D.L., Savee, J.D., & Savee, J.D. (2016). Influence of Oxygenation in Cyclic Hydrocarbons on Chain-Termination Reactions from R + O2: Tetrahydropyran and Cyclohexane [Conference Poster]. https://www.osti.gov/biblio/1373462 Publication ID: 51387
  • Papajak, E., Rotavera, B., Sheps, L., Taatjes, C.A., Zador, J., & Zador, J. (2016). Identification of combustion intermediates via photoionization: Large amplitude motions in alkyl- and ketohydroperoxides [Conference Poster]. https://www.osti.gov/biblio/1373149 Publication ID: 51304
  • Sheps, L. (2016). Competing first- and second-O2 addition pathways in low-T autoignition of tetrahydrofuran [Conference Poster]. https://www.osti.gov/biblio/1505268 Publication ID: 51208
  • Rotavera, B., Caravan, R.L., Ramasesha, K., Antonov, I.O., Papajak, E., Zador, J., Osborn, D.L., Taatjes, C.A., Sheps, L., & Sheps, L. (2016). Implications of Radical Ring-Opening Reactions on Ketohydroperoxide Formation: Cyclohexane and Tetrahydropyran [Conference Poster]. https://www.osti.gov/biblio/1420887 Publication ID: 50986
  • Sheps, L., Au, K., Scully, A.M., & Scully, A.M. (2015). Spectroscopy and reaction kinetics of a Criegee intermediate CH3CHOO using time-resolved broadband Cavity-enhanced Absorption Spectrometry [Conference Poster]. https://www.osti.gov/biblio/1323043 Publication ID: 45385
  • Welz, O., Burke, M.P., Antonov, I.O., Goldsmith, C.F., Savee, J.D., Osborn, D.L., Taatjes, C.A., Klippenstein, S.J., Sheps, L., & Sheps, L. (2015). New Insights into Low-Temperature Oxidation of Propane from Synchrotron Photoionization Mass Spectrometry and Multiscale Informatics Modeling. Journal of Physical Chemistry A, 119(28), pp. 7116-7129. https://doi.org/10.1021/acs.jpca.5b01008 Publication ID: 43738
  • Decker, Z., Au, K., Sheps, L., & Sheps, L. (2015). Reaction Kinetics of a Prototypical Criegee Intermediate Formaldehyde Oxide (CH2OO) with Isoprene [Presentation]. https://www.osti.gov/biblio/1327532 Publication ID: 44811
  • Eskola, A.J., Antonov, I.O., Sheps, L., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2015). KETOHYDROPEROXIDE FORMATION AND DECOMPOSITION IN CL-ATOM INITIATED OXIDATION OF N-BUTANE AND NEOPENTANE: ACHIEVEMENTS AND CHALLENGES [Conference Poster]. https://www.osti.gov/biblio/1339485 Publication ID: 44690
  • Eskola, A.J., M, S.A., Antonov, I.O., Sheps, L., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2015). Direct observation of ketohydroperoxide formation and decomposition in photolytically initiated oxidation of n-butane neopentane and diethylketone [Conference Poster]. https://www.osti.gov/biblio/1331614 Publication ID: 44131
  • Eskola, A.J., Antonov, I.O., Sheps, L., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2015). Time-resolved measurements of product formation in neopentane oxidation: a probe to investigate chain-branching mechanism [Conference Poster]. https://www.osti.gov/biblio/1257560 Publication ID: 43930
  • Sheps, L. (2015). Time-Resolved Broadband Cavity-Enhanced Absorption Spectrometry: [Conference Poster]. https://www.osti.gov/biblio/1261847 Publication ID: 44079
  • Savee, J.D., Antonov, I.O., Huang, H., Osborn, D.L., Sheps, L., Zador, J., Taatjes, C.A., & Taatjes, C.A. (2015). Influence of Oxygenation in Cyclic Hydrocarbons on Chain-Termination Reactions from R + O2: Tetrahydropyran and Cyclohexane [Conference Poster]. https://www.osti.gov/biblio/1261093 Publication ID: 44085
  • Savee, J.D., Papajak, E., Rotavera, B., Huang, H., Eskola, A.J., Welz, O., Sheps, L., Taatjes, C.A., Zador, J., Osborn, D.L., & Osborn, D.L. (2015). Direct observation and kinetics of a hydroperoxyalkyl radical (QOOH) [Conference Poster]. Science. https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84922432293&origin=inward Publication ID: 42817
  • Rotavera, B., Zador, J., Welz, O., Sheps, L., Scheer, A.M., Savee, J.D., Akbar Ali, M., Lee, T.S., Simmons, B., Osborn, D.L., Violi, A., Taatjes, C.A., & Taatjes, C.A. (2014). Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane. Journal of Physical Chemistry A, 118(44), pp. 10188-10200. https://doi.org/10.1021/jp507811d Publication ID: 38200
  • Sheps, L., Au, K., Scully, A.M., & Scully, A.M. (2014). UV absorption probing of the conformer-dependent reactivity of a Criegee intermediate CH3CHOO. Physical Chemistry Chemical Physics, 16(48), pp. 1-15. https://doi.org/10.1039/C4CP04408H Publication ID: 39232
  • Rotavera, B., Zador, J., Welz, O., Savee, J.D., Sheps, L., Osborn, D.L., Taatjes, C.A., Dillstom, T., Ali, M., Violi, A., & Violi, A. (2014). Decomposition Pathways and Product Formation from R + O2 Reactions in Low-Temperature Oxidation of 25-dimethylhexane [Presentation]. https://www.osti.gov/biblio/1502709 Publication ID: 38428
  • Scully, A.M., Sheps, L., & Sheps, L. (2014). UV Probing of the Reaction Kinetics of Two Criegee Intermediates [Presentation]. https://www.osti.gov/biblio/1496101 Publication ID: 37709
  • Sheps, L. (2014). UV Spectroscopy and Reaction Kinetics of Criegee Intermediates: CH2OO and CH3CHOO [Presentation]. https://www.osti.gov/biblio/1494412 Publication ID: 37817
  • Sheps, L. (2014). CRF Webpages [Presentation]. https://www.osti.gov/biblio/1695606 Publication ID: 40415
  • Sheps, L. (2014). UV spectroscopic probing of the reaction kinetics of Criegee intermediates CH2OO and the syn- and anti- isomers of CH3CHOO [Conference]. https://www.osti.gov/biblio/1142412 Publication ID: 40432
  • Sheps, L. (2014). Electronic States of the Quasi-linear Molecule Propargylene (HCCCH) from Negative Ion Photoelectron Spectroscopy. Journal of the American Chemical Society. https://doi.org/10.1021/ja5039984 Publication ID: 40499
  • Welz, O., Eskola, A.J., Sheps, L., Rotavera, B., Savee, J.D., Scheer, A.M., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2014). Rate coefficients of Criegee Intermediate (CH2OO and CH3CHOO) reactions with formic and acetic acid are close to their collision limit: Direct kinetics measurements and atmospheric implications. Undecided. https://www.osti.gov/biblio/1140587 Publication ID: 36928
  • Taatjes, C.A., Rotavera, B., Osborn, D.L., Welz, O., Sheps, L., Scheer, A.M., Savee, J.D., Simmons, B., & Simmons, B. (2014). Initial chemical steps in the low-temperature oxidation of 25-dimethylhexane. Journal of Physical Chemistry A. https://www.osti.gov/biblio/1140626 Publication ID: 36806
  • Sheps, L., Koning, P.B., & Koning, P.B. (2013). Novel Spectroscopic Method Reveals Intermediates over a Broad Spectrum [Presentation]. https://www.osti.gov/biblio/1675156 Publication ID: 31764
  • Eskola, A.J., Zador, J., Antonov, I.O., Sheps, L., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2013). Probing the Low-Temperature Chain-Branching Mechanism for n-Butane Autoignition Chemistry via Time-Resolved Measurements of Ketohydroperoxide Formation in Photolytically Initiated n-C4H10 Oxidation [Conference]. https://doi.org/10.1016/j.proci.2014.05.011 Publication ID: 31829
  • Sheps, L. (2013). Absolute ultraviolet absorption spectrum of Criegee intermediate CH2OO differs sharply from its action spectrum. Journal of Physical Chemistry Letters, 4(24), pp. 1-17. https://doi.org/10.1021/jz402191w Publication ID: 36183
  • Sheps, L. (2013). Absolute ultraviolet absorption spectrum of Criegee intermediate CH2OO differs sharply from its action spectrum. Journal of Physical Chemistry Letters, 4(24), pp. 1-11. https://doi.org/10.1021/jz402191w Publication ID: 36182
  • Rotavera, B., Welz, O., Sheps, L., Scheer, A.M., Savee, J.D., Osborn, D.L., Simmons, B., Taatjes, C.A., & Taatjes, C.A. (2013). Component-Centered Approach Towards Oxidation Studies of Complex Biofuels [Conference]. https://www.osti.gov/biblio/1106687 Publication ID: 34399
  • Sheps, L. (2013). Spectroscopy and chemical kinetics of formaldehyde oxide (CH2OO) using time-resolved broadband cavity-enhanced absorption spectroscopy [Conference]. https://www.osti.gov/biblio/1113277 Publication ID: 34269
  • Sheps, L., Welz, O., Zador, J., Savee, J.D., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2013). DETAILED ISOMER-RESOLVED KINETIC STUDY OF LOW-TEMPERATURE AUTOIGNITION CHEMISTRY OF PROPANE [Conference]. https://www.osti.gov/biblio/1113290 Publication ID: 34270
  • Taatjes, C.A., Welz, O., Osborn, D.L., Savee, J.D., Zador, J., Sheps, L., & Sheps, L. (2013). Low-Temperature Combustion Chemistry of n-Butanol: Principal Oxidation Pathways of Hydroxybutyl Radicals. Journal of Physical Chemistry A. https://www.osti.gov/biblio/1078873 Publication ID: 33165
  • Zador, J., Savee, J.D., Eskola, A.J., Sheps, L., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2013). Pathways in the Low-Temperature Oxidation Chemistry of Alcohols [Conference]. https://www.osti.gov/biblio/1073459 Publication ID: 32908
  • Sheps, L., Chandler, D., & Chandler, D. (2013). Time-resolved broadband cavity-enhanced absorption spectroscopy for chemical kinetics. https://doi.org/10.2172/1095949 Publication ID: 32821
  • Welz, O., Zador, J., Savee, J.D., Eskola, A.J., Sheps, L., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2012). Pathways in the Low-Temperature Oxidation Chemistry of Alcohols [Conference]. https://www.osti.gov/biblio/1062338 Publication ID: 30737
  • Savee, J.D., Eskola, A.J., Sheps, L., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2012). Low-temperature combustion chemistry of biofuels: Pathways in the low-temperature (550 – 700 K) oxidation chemistry of isobutanol and tert-butanol [Conference]. https://www.osti.gov/biblio/1116847 Publication ID: 29233
  • Welz, O., Zador, J., Savee, J.D., Sheps, L., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2012). Low-temperature oxidation chemistry of 1-butanol: A combined photoionization mass spectrometry and quantum-chemical/master-equation study [Conference]. https://www.osti.gov/biblio/1111361 Publication ID: 28823
  • Welz, O., Zador, J., Savee, J.D., Ng, M.Y., Meloni, G., Fernandes, R.X., Sheps, L., Simmons, B., Lee, T.S., Osborn, D.L., Taatjes, C.A., & Taatjes, C.A. (2012). Low-temperature combustion chemistry of biofuels: Pathways in the initial low-temperature (550 K-750 K) oxidation chemistry of isopentanol. Physical Chemistry Chemical Physics, 14(9), pp. 3112-3127. https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84863116585&origin=inward Publication ID: 24854
  • Sheps, L., Welz, O., Zador, J., Taatjes, C.A., & Taatjes, C.A. (2012). High-pressure low-temperature combustion chemistry: a combined experimental theoretical and modeling study of propane oxidation [Conference]. https://www.osti.gov/biblio/1078669 Publication ID: 26931
  • Taatjes, C.A., Welz, O., Zador, J., Sheps, L., Savee, J.D., Osborn, D.L., & Osborn, D.L. (2012). Low-Temperature Combustion Chemistry of 1-Butanol: A Synchrotron Photoionization Mass Spectrometry and Theoretical Study [Conference]. https://www.osti.gov/biblio/1062771 Publication ID: 26018
  • Taatjes, C.A., Eskola, A.J., Welz, O., Sheps, L., Osborn, D.L., Savee, J.D., & Savee, J.D. (2012). Low-Temperature Combustion Chemistry of Biofuels: Pathways in the Low-Temperature (550 ? 700 K) Oxidation Chemistry of Isobutanol and tert-Butanol. Proposed for publication in Proceedings of the Combustion Institute.. https://www.osti.gov/biblio/1062943 Publication ID: 25741
  • Taatjes, C.A., Welz, O., Zador, J., Simmons, B., Savee, J.D., Osborn, D.L., Sheps, L., & Sheps, L. (2011). Fundamental studies on the autoignition chemistry of isopentanol [Conference]. https://www.osti.gov/biblio/1110267 Publication ID: 21539
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