Journal Articles (* indicates undergraduate students)

M. D. Marshall and H. O. Leung, "Molecular Structures and Microwave Spectra of the Gas-Phase Homodimers of 3-Fluoro-1,2-epoxypropane and 3,3-Difluoro-1,2-epoxypropane," J. Phys. Chem. A 127, 6267 (2023), doi:10.1021/acs.jpca.3c03643

Helen O. Leung, Mark D. Marshall, and Seohyun Hong,* "Microwave Spectrum and Novel Molecular Structure of (Z)‑1-Chloro-3,3,3-trifluoropropene−Acetylene," J. Phys. Chem. A 127, 6241 (2023), doi:10.1021/acs.jpca.3c03517

Helen O. Leung, Mark D. Marshall, Seohyun Hong,* and Laboni Hoque,* "The microwave spectra and molecular structures of (Z)-1-chloro-3,3,3-trifluoropropene and its gas-phase heterodimer with the argon atom," Journal of Molecular Spectroscopy 394, 111779 (2023), doi: 10.1016/j.jms.2023.111779

Mark D. Marshall, Helen O. Leung, Sérgio R. Domingos, Anna Krin, Melanie Schnell, Nathan A. Seifert, Yunjie Xu, and Wolfgang Jäger, "Examining the gas-phase homodimers of 3,3,3-trifluoro-1,2-epoxypropane using quantum chemistry and microwave spectroscopy," Physical Chemistry Chemical Physics 24, 28495 (2022) doi: 10.1039/d2cp04663f
 
Helen O. Leung, Mark D. Marshall, Taha Z. Ahmad,* David W. Borden,* Caitlin A. Hoffman,* and Navie A. Kim,* "The microwave spectra and molecular structures of the chiral and achiral rotamers of 2,3,3-trifluoropropene and their gas-phase heterodimers with the argon atom," Journal of Molecular Spectroscopy 387, 111656 (2022), doi: 10.1016/j.jms.2022.111656.
 
Helen O. Leung, Mark D. Marshall, Aaron T. Bozzi,* Jonah R. Horowitz,* Andres C. Nino,* Hannah K. Tandon,* and Leonard Yoon,* "The microwave spectra and molecular structures of (E)-1-chloro-1,2-difluoroethylene and its complex with the argon atom," Journal of Molecular Spectroscopy 381, 111520 (2021), doi: 10.1016/j.jms.2021.111520
 
Helen O. Leung, Mark D. Marshall, and Eli Mlaver,*  "Straining to Put the Pieces Together: The Molecular Structure of (E)-1-Chloro-1,2-Difluoroethylene-Acetylene from Microwave Spectroscopy," Journal of Physical Chemistry A 125, 6722 (2021), doi: 10.1021/acs.jpca.1c05169

Helen O. Leung, Mark D. Marshall, Jonah R. Horowitz,* and Devon J. Stuart,* "The microwave spectrum and molecular structure of the gas-phase heterodimer formed between argon and glycidol," Journal of Molecular Spectroscopy 375, 111407 (2021), doi: 10.1016/j.jms.2020.111407

Mark D. Marshall, Helen O. Leung, Olivia Febles,* and Alexandra Gomez,* "The microwave spectra and molecular structures of (E)-1,3,3,3-tetrafluoropropene and its complex with the argon atom," Journal of Molecular Spectroscopy 374, 111379, (2020), doi: 10.1016/j.jms.2020.111379

Sérgio R. Domingos, Cristóbal Pérez, Mark D. Marshall, Helen O. Leung and Melanie Schnell, "Assessing the performance of rotational spectroscopy in chiral analysis," Chemical Science 11, 10863 (2020), doi: 10.1039/D0SC03752D (Open Access, Minireview).

Helen O. Leung, Mark D. Marshall, and Devon J. Stuart,* "Microwave Spectrum and Molecular Structure of 3-Fluoro-1,2-epoxypropane and the Unexpected Structure of Its Complex with the Argon Atom," Journal of Physical Chemistry A 124, 1798 (2020), doi: 10.1021/acs.jpca.0c00327

Helen O. Leung and Mark D. Marshall, "The Importance of How the Pieces Fit Together: the Microwave Spectrum and Molecular Structure of 2-Chloro-1,1-difluoroethylene–Acetylene," Journal of Physical Chemistry A 124, 1382 (2020), doi: 10.1021/acs.jpca.9b11861

Helen O. Leung and Mark D. Marshall, "Exploring the Sterically Disfavored Binding of Acetylene to a Geminal Olefinic Hydrogen-fluorine Atom Pair: The Microwave Spectrum and Molecular Structure of cis-1,2-Difluoroethylene-Acetylene," Journal of Chemical Physics 152, 034303 (2020), doi: 10.1063/1.5141073

Helen O. Leung and Mark D. Marshall, "Exploring the Forces Contributing to Noncovalent Bonding by Microwave Spectroscopy and Structural Characterization of Gas-phase Heterodimers of Protic Acids with Haloethylenes," Journal of Physical Chemistry A 123, 10846( 2019), doi: 10.1021/acs.jpca.9b07960 (Open Access, Invited Feature Article, ACS Editors' Choice)

Helen O. Leung and Mark D. Marshall, " Finding the Better fit: the Microwave Spectrum and Sterically Preferred Structure of Trans-1,2-Difluoroethylene-Hydrogen Chloride," Journal of Physical Chemistry A 122, 8363 (2018), doi: 10.1021/acs.jpca.8b07992

Mark D. Marshall and Helen O. Leung, "The Microwave Spectrum and Molecular Structure of 3,3-Difluoro-1,2-Epoxypropane and Its Complex with the Argon Atom," Journal of Molecular Spectroscopy 350, 18 (2018), doi: 10.1016/j.jms.2018.05.003.

Mark D. Marshall, Helen O. Leung, Kevin Wang,* and Mbatang Desmond Acha,* "Microwave Spectrum and Molecular Structure of the Chiral Tagging Candidate, 3,3,3-Trifluoro-1,2-Epoxypropane and Its Complex with the Argon Atom," Journal of Physical Chemistry A, 122, 4670 (2018),  doi: 10.1021/acs.jpca.8b02550.

H. O. Leung, M. D. Marshall, and N. D. Khan,* "The Microwave Spectrum and Molecular Structure of (Z)-1-Chloro-2-fluoroethylene−Acetylene: Demonstrating the Importance of the Balance Between Steric and Electrostatic Interactions in Heterodimer Formation," Journal of Physical Chemistry A 121, 5651 (2017), doi: 10.1021/acs.jpca.7b05101.

C. T. Dewberry, J. L. Mueller,* R. B. Mackenzie, B. A. Timp, M. D. Marshall, H. O. Leung, and K. R. Leopold, "The Effect of Ortho-fluorination on Intermolecular Interactions of Pyridine: Microwave Spectrum and Structure of the CO2-2,6-Difluoropyridine Weakly Bound Complex," Journal of Molecular Structure 1146, 373 (2017), doi: 10.1016/j.molstruc.2017.06.015.

H. O. Leung, M. D. Marshall, M. A. Wronkovich,* "The Microwave Spectrum and Molecular Structure of Ar-2,3,3,3-Tetrafluoropropene," Journal of Molecular Spectroscopy 337, 80 (2017), doi: 10.1016/j.jms.2017.04.012.

N. A. Seifert, D. P. Zaleski, R. Fehnel, M. Goswami, B. H. Pate, K. K. Lehmann, H. O. Leung, M. D. Marshall, J. F. Stanton, "The Gas-phase Structure of the Asymmetric, Trans-Dinitrogen Tetroxide (N2O4), Formed by Dimerization of Nitrogen Dioxide (NO2), from Rotational Spectroscopy and Ab Initio Quantum Chemistry," Journal of Chemical Physics 146, 134305 (2017), doi: 10.1063/1.4979182.

H. O. Leung and M. D. Marshall, "Effect of Chlorine Substitution in Modulating the Relative Importance of Two Intermolecular Interactions: the Microwave Spectrum and Molecular Structure of (E)-1-Chloro-2-fluoroethylene-HCl," Journal of Physical Chemistry A 120, 7955 (2016), doi: 10.1021/acs.jpca.6b07739.

H. O. Leung, M. D. Marshall, and A. J. Lee,* "The Microwave Spectrum and Molecular Structure of (E)-1-Chloro-2-fluoroethylene-HF: Revealing the Balance Among Electrostatics, Sterics, and Resonance in Intermolecular Interactions," Journal of Physical Chemistry A 120, 7935 (2016), doi: 10.1021/acs.jpca.6b07252.

H. O. Leung, M. D. Marshall, J. P. Messinger,* G. S. Knowlton,* K. M. Sundheim,* and J. C. Cheung-Lau,* "The Microwave Spectra and Molecular Structures of 2-Chloro-1,1-difluoroethylene and Its Complex with the Argon Atom," Journal of Molecular Spectroscopy 305, 25 (2014), doi: 10.1016/j.jms.2014.09.011.

H. O. Leung and M. D. Marshall, "Effect of Acid Identity on the Geometry of Intermolecular Complexes: The Microwave Spectrum and Molecular Structure of Vinyl Chloride-HF," Journal of Physical Chemistry A 118, 9783 (2014), doi: 10.1021/jp508278d.

H. O. Leung, M. D. Marshall, J. L. Mueller,* and B. K. Amberger,* "The Molecular Structure of and Interconversion Tunneling in the Argon-cis-1,2-Difluoroethylene Complex," Journal of Chemical Physics 139, 134303 (2013).

H. O. Leung, M. D. Marshall, and F. Feng,* "Microwave Spectrum and Molecular Structure of Vinyl Chloride-Acetylene, a Side Binding Complex," Journal of Physical Chemistry A 117, 13419 (2013).

M. D. Marshall, H. O. Leung, and C. E. Calvert,* "Molecular Structure of the Argon-(Z)-1­-­Chloro-­2-fluoroethylene Complex from Chirped-pulse and Narrow-band Fourier Transform Microwave Spectroscopy," Journal of Molecular Spectroscopy 280, 97(2012).

H. O. Leung, M. D. Marshall, A. T. Bozzi,* P. M. Cohen,* and M. Lam,* "Microwave Spectrum and Molecular Structure of the 1-Chloro-1-fluoroethylene-Hydrogen Fluoride Complex," Journal of Molecular Spectroscopy 267, 43(2011).

M. D. Marshall, H. O. Leung, B. Q. Scheetz,* J. E. Thaler,* and J. S. Muenter, "A Chirped Pulse Fourier Transform Microwave Study of the Refrigerant Alternative 2,3,3,3-Tetrafluoropropene," Journal of Molecular Spectroscopy 266, 37(2011).

H. O. Leung, M. D. Marshall, and D. Grimes,* "Rotational Spectroscopy and Molecular Structure of the 1-Chloro-1-fluoroethylene-Acetylene Complex," Journal of Chemical Physics 134, 034303 (2011).

H. O. Leung and M. D. Marshall, "Rotational Spectra of 34S- and 33S-containing Isotopolgues of Laser Ablation Generated Tin Monosulfide," Journal of Molecular Spectroscopy 265, 52 (2011).

H. O. Leung, M. D. Marshall, M. R. Ray,* and J. T. Kang,* "Rotational  Spectroscopy and Molecular Structure of the 1,1,2-Trifluoroethylene-Hydrogen Chloride Compex," Journal of Physical Chemistry A 114, 10975 (2010).

H. O. Leung, M. D. Marshall, and B. K. Amberger,* "Fourier Transform Microwave Spectroscopy and Molecular Structure of the Trans-1,2-difluoroethylene-Hydrogen Fluoride Compex," Journal of Chemical Physics 131, 204302 (2009).

H. O. Leung, M. D. Marshall, T. L. Drake,* T. Pudlik,* N. Savji,* and D. W. McCune,* "Fourier Transform Microwave Spectroscopy and Molecular Structure of the 1,1-Difluoroethylene-Hydrogen Fluoride Complex," Journal of Chemical Physics 131, 204301 (2009).

H. O. Leung, M. D. Marshall, A. L. Vasta,* and N. C. Craig, "Microwave Spectra of Eight Isotopic Modifications of 1-Chloro-1-Fluoroethylene," Journal of Molecular Spectroscopy 253, 116 (2009).

C. S. Brauer, G. Sedo, E. Dahlke, S. Wu, E. M. Grumstrup, K. R. Leopold, M. D. Marshall, H. O. Leung, and D. G. Truhlar, "Effects of 18O Isotopic Substitution on the Rotational Spectra and Potential Splitting in the OH-OH2 complex: Improved Measurements for 16OH-16OH2 and 18OH-18OH2, New Measurements for the Mixed Isotopic Forms, and Ab Initio Calculations of the 2A' - 2A'' Energy Separation," Journal of Chemical Physics 129, 104304 (2008).

H. O. Leung, M. D. Marshall, W. T. Cashion,* and V. L. Chen,* "Rotational Spectroscopy and Molecular Structure of the 1,1,2-Trifluoroethylene-Acetylene Complex," Journal of Chemical Physics 128, 064315 (2008).

H. O. Leung and M. D. Marshall, "Rotational Spectroscopy and Molecular Structure of 1,1,2-Trifluoroethylene and the 1,1,2-Trifluoroethylene-Hydrogen Fluoride Complex," Journal of Chemical Physics 126, 114310 (2007).

H. O. Leung and M. D. Marshall, "Rotational Spectroscopy and Molecular Structure of the 1,1-Difluoroethylene-Acetylene Complex," Journal of Chemical Physics 125, 154301 (2006).

C. S. Bauer, G. Sedo, E. K. Grumstrup, K. R. Leopold, M. D. Marshall, and H. O. Leung, "Effects of Partially Quenched Orbital Angular Momentum on the Microwave Spectrum and Magnetic Hyperfine Splitting in the OH-water Complex," Chemical Physics Letters 401, 420 (2005).

H. O. Leung, W. T. Cashion,* K. K. Duncan,* C. L. Hagan,* and S. Joo,* "Nuclear Quadrupole Hyperfine Structure in the Microwave Spectrum of HCl-N2O: Electric Field Gradient Perturbation of N2O by HCl," Journal of Chemical Physics 121, 237 (2004).

H. O. Leung, O. M. Ibidapo,* P. I. Abruña,* and M. B. Bianchi,* "Nuclear Hyperfine Coupling Interactions in the Rotational Spectra of the Linear and Bent Isomers of HF-N2O," Journal of Molecular Spectroscopy 222, 3 (2003).

I. B. Pollack, M. Tsiouris, H. O. Leung, and M. I. Lester, "Infrared Action Spectroscopy and Time-Resolved Dynamics of the OD-CO Reactant Complex," Journal of Chemical Physics 119, 118 (2003).

M. Tsiouris, I. B. Pollack, H. O. Leung, M. D. Marshall, and M. I. Lester, "OD-N2: Infrared Spectroscopy, Potential Anisotropy, and Predissociation Dynamics from IR-UV Double Resonance Studies," Journal of Chemical Physics 116, 913 (2002).

H. O. Leung, A. M. Osowski,* O. A. Oyeyemi,* "Rotational Spectrum and Molecular Structure of OCS-N2O," Journal of Chemical Physics 114, 4829 (2001).

R. A. Peebles, S. A. Peebles, R. L. Kuczkowski, and H. O. Leung, "Isotopic Studies, Structure and Modeling of the Nitrous Oxide-Acetylene Complex," Journal of Physical Chemistry A 103, 10813 (1999).

M. D. Marshall and H. O. Leung "The Molecular Structure of CO2-N2O," Journal of Molecular Spectroscopy 196, 149 (1999).

H. O. Leung, "Rotational Spectroscopy and Molecular Structure of 15N2-14N2O," Journal of Chemical Physics 110, 4394 (1999).

H. O. Leung, "The Rotational Spectrum and Nuclear Quadrupole Hyperfine Structure of CO2-N2O," Journal of Chemical Physics 108, 3955 (1998).

H. O. Leung, D. Gangwani,* and J.-U. Grabow, "Nuclear Quadrupole Hyperfine Structure in the Microwave Spectrum of Ar-N2O," Journal of Molecular Spectroscopy 184, 106 (1997).

H. O. Leung, "The Microwave Spectrum and Nuclear Quadrupole Hyperfine Structure of HCCH-N2O," Journal of Chemical Physics 107, 2232 (1997).

H. O. Leung, "Nuclear Quadrupole Hyperfine Structure in the Rotational Spectra of HCCH-N2O and Ar-N2O," Chemical Communications 1996, 2525 (1996).

Books Published

H. O. Leung and M. D. Marshall, Problems and Solutions to Accompany Chang and Thoman's Physical Chemistry for the Chemical Sciences, University Science Books, Mill Valley, California, 2014.

Helen O. Leung and Mark D. Marshall, Problems and Solutions to accompany Donald A. McQuarrie's Quantum Chemistry Second Edition (University Science Books, Sausalito, California, 2008).

Mark D. Marshall and Helen O. Leung, Instructors' Manual to accompany Chang's Physical Chemistry for the Biosciences (University Science Books, Sausalito, California, 2005).

Mark D. Marshall and Helen O. Leung, Problems and Solutions to accompany Chang's Physical Chemistry for the Biosciences (University Science Books, Sausalito, California, 2005).

Helen O. Leung and Mark D. Marshall, Problems and Solutions to accompany Chang's Physical Chemistry for the Chemical and Biological Sciences (University Science Books, Sausalito, California, 2000).