Helen O. Leung
Professor
Department of Chemistry
Amherst College
P.O. Box 5000
Amherst, MA  01002
413-542-2660
hleung

(Please add @amherst.edu after the username for email)

B.S. (Chemistry) - California State University, Northridge (1982)
B.A. (Biology) - California State University, Northridge (1983)
A.M. (Chemistry) - Harvard University (1985)
Ph.D. (Chemistry) - Harvard University (1988)

Research Interest
Selected Publications
Book
Recent Talks
Recent Posters

---

Research Interests
Fourier transform microwave spectroscopy of weakly bound molecules

Some of the molecules studied in our lab (with undergraduate researchers listed in parentheses) are

Ar-N2O:	Ar-^14N2O	(Deepa Dangwani)
HCCH-N2O:	HCCH-^14N2O, HCCH-^15N^14NO
CO2-N2O:	CO2-^14N2O, CO2-^15N^14NO
N2-N2O:	^15N2-^14N2O
HCl-N2O:	H^35Cl-^14N2O, H^37Cl-^14N2O, H^35Cl-^15N^14NO, H^37Cl-^15N^14NO, H^35Cl-^15N2O, D^35Cl-^15N2O	(Winn Cashion, Katharine Duncan, Christine Hagan, Sujin Joo)
OCS-N2O:	OC^32S-^14N2O, OC^32S-^15N^14NO, OC^32S-^15N2O, OC^34S-^15N2O	(Anne Osowski, Olayinka Oyeyemi)
HF-N2O:	HF-^15N2O, HF-^15N^14NO, HF-^14N^15NO,  DF-^15N2O, DF-^15N^14NO, DF-^14N^15NO	(Oluwatoyin Ibidapo, Patricia Abruña, Mary Bianchi)
Imidazole:	imidazole-^14N2, imidazole-^15N-1, imidazole-^15N-3, imidazole-^15N2
Ar-Imidazole:	Ar-imidazole-^14N2, Ar-imidazole-^15N-1, Ar-imidazole-^15N-3, Ar-imidazole-^15N2	(Ryan Welch)
HCCH-CH2CF2:	HCCH-CH2CF2, HCCD-CH2CF2, DCCD-CH2CF2, H^13C^13CH-CH2CF2, H^13CCH-CH2CF2, HC^13CH-CH2CF2, HCCH-^13CH2CF2, HCCH-CH2^13CF2
HCCH-CHFCF2:	HCCH-CHFCF2, HCCD-CHFCF2, H^13C^13CH-CHFCF2, HCCH-CHF^13CF2, H^13CCH-CHFCF2, HC^13CH-CHFCF2	(Winn Cashion, Vincent Chen)
HF-CHFCF2:	HF-CHFCF2, DF-CHFCF2, HF-^13CHFCF2, HF-CHF^13CF2
CHClCF2:	CH^35ClCF2, CH^37ClCF2, ^13CH^35ClCF2, CH^35Cl^13CF2	(Jasmina Cheung-Lau)
CFClCH2:	CF^35ClCH2, CF^37ClCH2, ^13CF^35ClCH2, CF^35Cl^13CH2, ^13CF^37ClCH2, CF^37Cl^13CH2, (E)- CF^35ClCHD, (Z)- CF^35ClCHD	(Andrew Vasta)
HF-CH2CF2	HF-CH2CF2, HF-^13CH2CF2, HF-CH2^13CF2, DF-CH2CF2, DF-^13CH2CF2, DF-CH2^13CF2	(Tasha Drake, Tadeusz Pudlik, Daniel McCune, Nazir Savji)
(E)-CFClCHF:	CF^35ClCHF, CF^37ClCHF, CF^35Cl^13CHF, ^13CF^35ClCHF	(Aaron Bozzi)
HF-trans-CHFCF:	HF-CHFCF, HF-^13CHFCF, HF-CHF^13CF, DF-CHFCF, DF-^13CHFCF, DF-CHF^13CF	(Brent Amberger)
HCl-CHFCF2:	H^35Cl-CHFCF2, H^37Cl-CHFCF2	(Margaret Ray, Justin Kang)

---

Selected Publications
(* - undergraduate students)

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
"Setting Up Research: Getting Creative," Chemical and Engineering News 79, 205 (2001)

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

H. O. Leung and M. D. Marshall, "Problems and Solutions to Accompany Donald A. McQuarrie's Quantum Chemistry Second Edition," University Science Books, Sausalito, California, 2008.

M. D. Marshall and H. O. Leung, "Instructors' Manual to Accompany Chang's Physical Chemistry for the Biosciences," University Science Books, Sausalito, California, 2005.

M. D. Marshall and H. O. Leung, "Problems and Solutions to Accompany Chang's Physical Chemistry for the Biosciences," University Science Books, Sausalito, California, 2005.

H. O. Leung and M. D. Marshall, "Problems and Solutions to Accompany Chang's Physical Chemistry for the Chemical and Biological Sciences," University Science Books, Sausalito, California, 2000.

---

Recent Talks
(* - undergraduate students)

M. R. Ray,* H. O. Leung, and M. D. Marshall, "Fourier Transform Microwave Spectroscopy of the Trifluoroethylene-Hydrogen Chloride Complex," The Sixty‑Third International Symposium on Molecular Spectroscopy, talk WF03, Columbus, Ohio, 6/18/08.

B. K. Amberger,* H. O. Leung, and M. D. Marshall, "Fourier Transform Microwave Spectroscopy of the trans-1,2-Difluoroethylene-Hydrogen Fluoride Complex," The Sixty‑Third International Symposium on Molecular Spectroscopy, talk WF04, Columbus, Ohio, 6/18/08.

M. D. Marshall, H. O. Leung, and J. C. Cheung-Lau,* "The Microwave Spectrum and Molecular Structure of 2-Chloro-1,1-Difluoroethylene and Progress Towards Its Complexes with Argon and Hydrogen Fluoride," The Sixty-Second International Symposium on Molecular Spectroscopy, talk RG11, Columbus, Ohio, 6/21/07.

H. O. Leung and M. D. Marshall, "Fourier Transform Microwave Spectroscopy of the 1-Chloro-1-Fluoroethylene Monomer and the Acetylene-1-Chloro-1-Fluoroethylene Complex," The Sixty-Second International Symposium on Molecular Spectroscopy, talk RG10, Columbus, Ohio, 6/21/07.

H. O. Leung, M. D. Marshall, and W. T. Cashion,* "The Microwave Spectrum and Molecular Structure of Trifluoroethylene-Acetylene," The Sixty-First International Symposium on Molecular Spectroscopy, talk RE12, Columbus, Ohio, 6/22/06.

M. D. Marshall and H. O. Leung, "The Microwave Spectrum and Molecular Structure of Trifluoroethylene-Hydrogen Fluoride," The Sixty-First International Symposium on Molecular Spectroscopy, talk RE11, Columbus, Ohio, 6/22/06.

C. S. Brauer, G. Sedo, E. M. Grumstrup, K. R. Leopold, M. D. Marshall, and H. O. Leung, "Microwave Spectra of Isotopically Substituted Forms of OH-H₂O," The Sixty-First International Symposium on Molecular Spectroscopy, talk TE07, Columbus, Ohio, 6/20/06.

C. S. Brauer, G. Sedo, E. M. Grumstrup, K. R. Leopold, M. D. Marshall, and H. O. Leung, "Microwave Observation of the OH-H₂O Radical Complex," The Sixtieth International Symposium on Molecular Spectroscopy, talk FC02, Columbus, Ohio, 6/24/05.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of Acetylene-1,1-Difluoroethylene," The Sixtieth International Symposium on Molecular Spectroscopy, talk RC01, Columbus, Ohio, 6/23/05.

K. R. Leopold, C. S. Brauer, M. B. Craddock, G. Sedo, E. M. Grumstrup, M. D. Marshall, and H. O. Leung, "Charge Redistribution in Hydrogen Bonded Systems," The 229th National Meeting of the American Chemical Society, Division of Physical Chemistry, Paper 027, San Diego, CA, 3/13/05.

H. O. Leung, "Microwave Spectroscopy of Weakly Bound Complexes:  Easier Synthesis and Smaller Force Constants, but It All Started Here," California State University, Northridge, 3/30/04.

R. Welch* and H. O. Leung, "Fourier Transform Microwave Spectroscopy of Argon-Imidazole," The Fifty-Eighth International Symposium on Molecular Spectroscopy, talk MH11, Columbus, Ohio, 6/16/03.

O. M. Ibidapo,* P. I. Abruna,* M. B. Bianchi,* and H. O. Leung, "Nuclear Quadrupole Coupling Interactions in the Rotational Spectra of the Linear and Bent Isomers of HF-N₂O," The Fifty-Seventh International Symposium on Molecular Spectroscopy, talk MI12, Columbus, Ohio, 6/17/02.

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," The Fifty-Seventh International Symposium on Molecular Spectroscopy, talk MJ02, Columbus, Ohio, 6/17/02.

H. O. Leung, "Fourier Transform Microwave Spectroscopy: Probing Molecular Structures, Electronic Distributions, and Potential Energy Surfaces," Williams College, 2/5/02.

H. O. Leung, "Exploring Molecular Properties with Microwave Spectroscopy: Where we have been, and Where We Are Going Next," Amherst College, 11/26/01.

H. O. Leung, "Fourier Transform Microwave Spectroscopy: Probing Molecular Structures, Electronic Distributions, and Potential Energy Surfaces," Amherst College, 10/5/01.

I. B. Pollack, M. Tsiouris, H. O. Leung, and M. I. Lester, "OD-N₂: Infrared Spectroscopy, Potential Anisotropy, and Predissociation Dynamics from IR-UV Double Resonance Studies," The Fifty-sixth International Symposium on Molecular Spectroscopy, talk MF13, Columbus, Ohio, 6/11/01.

H. O. Leung, "Research as an Essential Component of Education in Chemistry at a Principally Undergraduate Institution," (Invited) The 220th National Meeting of the American Chemical Society, Envisioning the Chemical Sciences: Perspectives from Camille & Henry Dreyfus Foundation Awardees, Paper 102, Washington, D.C., 8/21/00.

H. O. Leung, "Perturbations to Electric Field Gradients in N₂O-containing van der Waals Complexes," (Invited) The Twenty-Ninth Northeast Regional American Chemical Society Meeting, Spectroscopy of Ions, Radicals, Complexes, and Multiconformational Molecules, University of Connecticut, Storrs, 6/20/00.

O. Oyeyemi* and H. O. Leung, "Rotational Spectroscopy of OCS-N₂O," The Fifty-Fifth International Symposium on Molecular Spectroscopy, talk WE05, Columbus, Ohio, 6/14/00.

H. O. Leung and O. Oyeyemi,* "Fourier Transform Microwave Spectroscopy of OCS-N₂O," The Second Northeast Microwave Symposium, University of Connecticut, 4/8/00.

H. O. Leung, "¹⁴N Hyperfine Splittings in the Microwave Spectrum of Four Isotopomers of N₂O-HCl," The Fifty-fourth International Symposium on Molecular Spectroscopy, talk RG06, Columbus, Ohio, 6/17/99.

H. O. Leung, "Progress in the Spectroscopy of HCl-N₂O," The First Northeast Microwave Symposium, University of Connecticut, 3/27/99.

M. D. Marshall and H. O. Leung, "The Structure of CO₂-N₂O Determined by Fourier Transform Microwave Spectroscopy of the ¹⁵N¹⁴NO-containing iostopomer," The Fifty-third International Symposium on Molecular Spectroscopy, talk FD07, Columbus, Ohio, 6/19/98.

H. O. Leung, "Rotational Spectroscopy and Molecular Structure of ¹⁵N₂-¹⁴N₂O," The Fifty-third International Symposium on Molecular Spectroscopy, talk WI15, Columbus, Ohio, 6/17/98.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of N₂O-containing van der Waals Molecules," Mount Holyoke College, South Hadley, 10/1/97.

H. O. Leung, "The Rotational Spectrum and Nuclear Quadrupole Hyperfine Structure of CO₂-N₂O," The Fifty-second International Symposium on Molecular Spectroscopy, talk WI14, Columbus, Ohio, 6/18/97.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of N₂O-containing Molecules," University of Massachusetts, Amherst, 4/3/97.

H. O. Leung and D. Gangwani*, "Fourier Transform Microwave Spectroscopy of Ar-N₂O and HCCH-N₂O," The Fifty-first International Symposium on Molecular Spectroscopy, talk TD03, Columbus, Ohio, 6/96.

D. Gangwani* and H. O. Leung, "Structural Determination of Ar-N₂O," American Chemical Society Undergraduate Chemistry Research Symposium, Williams College, Massachusetts, 4/96.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of Weakly Bound Molecules," (Invited)  The Twenty-Eighth Great Lakes Regional ACS meeting, Spectroscopy in Modern Chemistry, La Crosse, Wisconsin, 6/95.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of HCCH-N₂O" The Fiftieth Symposium on Molecular Spectroscopy, talk RI02, Columbus, Ohio, 6/95.

V. Prasad* and H. O. Leung, "Fourier Transform Microwave Spectroscopy of Methyl Propiolate," American Chemical Society Undergraduate Chemistry Research Symposium, Trinity College, Connecticut, 4/95.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of Weakly Bound Molecules," University of Connecticut, 4/94.

H. O. Leung, "Van der Waals Molecules: Their Bonds May Be Weak, but They Can't Be Ignored," Sigma Xi Lecture, Mount Holyoke College, 2/94.

H. O. Leung, "Weakly Bound Molecules and Fourier Transform Microwave Spectroscopy: a Natural Partnership," Mount Holyoke College, 2/93 and 12/93.

H. O. Leung, "Fourier Transform Microwave Spectroscopy of Weakly Bound Molecules," University of Massachusetts, Amherst, 11/93.

---

Recent Posters
(* - undergraduate students)

C. S. Brauer, G. Sedo, E. M. 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," The 229th National Meeting of the American Chemical Society, Division of Physical Chemistry, Paper 323, San Diego, CA, 3/16/05.

H. O. Leung, W. T. Cashion,* K. K. Duncan,* C. L. Hagan,* and S. Joo,* "Rotational Spectroscopy and Nuclear Quadrupole Hyperfine Structure in Six Isotopomers of HCl-N₂O," The 228th National Meeting of the American Chemical Society, Division of Physical Chemistry, paper 512, Philadelphia, Pennsylvania, 8/25/04.

H. O. Leung, A. M. Osowski,* and O. A. Oyeyemi,* "Molecular Structure of OCS-N₂O," The 220th National Meeting of the American Chemical Society, Division of Physical Chemistry, paper 367, Washington, D.C., 8/23/00.

H. O. Leung, "The Structures of the van der Waals Molecules CO₂-N₂O and N₂-N₂O and Electric Field Gradient Perturbations in These Complexes," The 216th American Chemical Society National Meeting, Division of Physical Chemistry, paper 332, Boston, Massachusetts, 8/25/98.

H. O. Leung, "The Effects of van der Waals Bond Formation on Electric Field Gradients in N₂O," Conference on Optical, Electric and Magnetic Properties of Molecules, Cambridge, England, 7/11/97.

H. O. Leung, "Electric Field Gradient Perturbations in Some N₂O-containing Complexes," The 213th American Chemical Society National Meeting, Division of Physical Chemistry, paper 127,  San Francisco, California, 4/13/97.

D. Gangwani* and H. O. Leung, "Structural Determination of Ar-N₂O," Women in Science Conference, Smith College, Massachusetts, 3/30/96.

---