Peter B. Armentrout

Jennifer S. Shumaker-Parry


Distinguished Professor and Cannon Fellow

B.S. Case Western Reserve University, 1975
Ph.D. California Institute of Technology, 1980
Postdoctoral, Bell Labs, 1981


Phone: (801) 581-7885

Office: 3402 HEB-S


Armentrout Research Group Site

Activities & Awards

  • Presidential Young Investigator, National Science Foundation, 1984-89
  • Alfred P. Sloan Research Fellow, 1986-1990
  • Camille and Henry Dreyfus Teacher-Scholar, 1987-1992
  • Fellow, AAAS, 1992; APS, 1994; JSPS, 1999
  • Buck-Whitney Award, ACS Eastern New York Section, 1993
  • University of Utah Distinguished Research Award, 1994
  • Mack Memorial Award Lecturer, Dept. of Chem., Ohio State University, 1997
  • Biemann Medal, Am. Soc. Mass Spectrometry, 2001
  • Utah Award of Chemistry, American Chemical Society, 2002
  • Cannon Fellow, Chemistry Department, University of Utah, 2003-present
  • Phi Kappa Phi Honor Society, 2004
  • Outstanding Alumnus of the Year, Dept. Chem., Case Western Reserve University, 2004
  • Field and Franklin Award in Mass Spectrometry, American Chemical Society, 2009
  • U of U Rosenblatt Prize for Excellence, 2011
  • Editorial Board: current, Int. J. Mass Spectrom., formerly, J. Am. Chem. Soc., J. Chem. Phys., J. Phys. Chem., Organometallics, J. Am. Soc. Mass Spectrom.; J. Cluster Science
  • Governor's Medal for Science and Technology Award, Utah, 2010
  • R. W. Parry Teaching Award, Department of Chemistry, University of Utah, 2011
  • Morino Lectureship, Morino Foundation of Japan and Kobe University, Japan, 2011

  • Honoree of Special Issue of International Journal of Mass Spectrometry, Vol. 330-332, 2012

  • Honoree of Special Issue of Journal of Physical Chemistry A, Vol. 117, 2013

Short Biography – Peter B. Armentrout

Professor Armentrout was born in Dayton, Ohio on March 13, 1953. He received a B.S. degree with highest honors in 1975 from Case Western Reserve University, Cleveland, Ohio. While at Case, Prof. Armentrout conducted research with Prof. Rob Dunbar on photodissociation spectroscopy of molecular ions which led to his interest in ion-molecule chemistry. After bicycling to California during the summer of 1975, he joined Prof. Jack Beauchamp at Caltech where he was awarded the Blanche A. Mowrer Memorial Fellowship. At Caltech, he constructed an ion beam apparatus designed to study the hyperthermal reactivity of atomic uranium and other metal ions; work which comprised his Ph.D. thesis, awarded in 1980. That January, Prof. Armentrout became a postdoctoral member of staff at Bell Labs in Murray Hill, New Jersey, working with Dr. Robert S. Freund. There he studied electron impact ionization of metastable atoms and molecules.

In July of 1981, Prof. Armentrout became an assistant professor at the University of California at Berkeley. He initiated a program which has come to study a wide spectrum of chemistries (primarily of transition metal species) by using ion-beam mass spectrometry. While at Berkeley, he was awarded a Camille and Henry Dreyfus Grant for Newly Appointed Faculty in Chemistry (1981), a NSF Presidential Young Investigator Award in its inception year (1984), and an Alfred P. Sloan Research Fellowship (1986). In 1987, he joined the faculty at the University of Utah as an associate professor where he was awarded a Camille and Henry Dreyfus Teacher-Scholar Grant (1987). In 1989, he was promoted to full professor. He has been recognized at Utah with an Outstanding Undergraduate Teaching Award from the Chemistry Department (1989) and the University-wide Distinguished Research Award (1994). He was the recipient of the Buck-Whitney Award from the American Chemical Society Eastern New York Section (1993) and in 1997, the graduate students at the Ohio State University Department of Chemistry selected Professor Armentrout as their Mack Memorial Award Lecturer. In 1998, he was promoted to Distinguished Professor of Chemistry and named Cannon Fellow in 2003. He received the Biemann Medal from the American Society of Mass Spectrometry in 2001 and the Utah Award of Chemistry from the Utah Sections of the American Chemical Society in 2003.

Professor Armentrout is a member of the editorial boards of the Journal of Physical Chemistry, the Journal of Chemical Physics, and the International Journal of Mass Spectrometry and Ion Processes, and formerly of the Journal of the American Chemical Society, Organometallics, and the Journal of Cluster Science (charter member). He is a member of the American Chemical Society, American Physical Society (fellow), American Society for Mass Spectrometry, and the American Association for the Advancement of Science (fellow). He presently has over 350 research publications that have appeared in the literature. Twenty-four students have received their Ph.D.s with Professor Armentrout.

In 1983, he married his high school sweetheart, Mary Ann White. They have three children, Matthew, Patricia, and Erin.

Research Interests

Our research provides a detailed understanding of the thermochemistry, kinetics, and dynamics of simple and complex chemical reactions. Our group seeks to understand, from a fundamental viewpoint, reactions involved in biological chemistry, catalysis, surface chemistry, organometallic chemistry, and plasma chemistry. Techniques involved include mass spectrometry, ion beams, molecular beams, laser spectroscopy, and ab initio theory.


Chemistry of state-selected atomic metal ions. Transition metals have an abundance of low-lying electronic states that we have shown for 1st-row metals can have very different reactivity. We have recently developed a novel ion mobility source that should permit such studies to be extended to the 2nd- and 3rd- row metals where spin-orbit interactions become important.

Chemistry of unsaturated organometallic complexes. By varying the number and types of ligands attached to metal ions, we study periodic trends, the influence of ligand substitution, and the effects of metal oxidation state on reactivity. These studies provide quantitative thermodynamic data and qualitative electronic information on unsaturated organometallic complexes: the key intermediates in homogeneous catalysis.

Chemistry of solvated ions. Gas-phase solvated ions are important species in the atmosphere and in aerosols and provide a bridge between phenomena in condensed phases and the gas phase. Detailed experiments on such species yield quantitative information that cannot be obtained easily in the condensed phase.

Thermochemistry of metal ions and protons interacting with biological molecules. Our work includes some of the first measurements of the binding energies of Li+, Na+ K+, and Rb+ with the nucleic acid bases, amino acids, and small peptides. The thermochemistry of protonated peptides is also being examined.

Chemistry of metal cluster ions. Laser vaporization, supersonic expansion techniques generate cold transition metal cluster ions that can be size-selected using mass spectrometry. We measure the thermodynamic stabilities of these clusters and their reactivity with a variety of molecules. These studies provide quantitative data relevant to surface chemistry and heterogeneous catalysis.

Environmental chemistry. A long standing interest has involved an investigation of the thermochemistry of systems having potential importance in the clean up of nuclear waste sites.

Threshold behavior: theory and experiment. A theoretical understanding of the kinetic energy dependence of reaction cross sections is in its infancy. We are developing theoretical models that include application of statistical theories, reaction dynamics, and non-adiabatic effects.

Ab initio theory. We consistently apply ab initio theory to provide structures, molecular parameters, and bond energies for use in the analysis and interpretation of our experimental results.

Selected Publications

    1. “Metal-Cyclopentadienyl Bond Energies in Metallocene Cations Measured Using Threshold Collision-Induced Dissociation Mass Spectrometry” Rowland, T. G.; Sztáray, B.; Armentrout, P. B. J. Phys. Chem. A (Peter B. Armentrout Festschrift)2013, 117, 1299-1309. DOI: 10.1021/jp307418c

    2. “Critical Evaluation of Kinetic Method Measurements: Possible Origins of Non-linear Effects” Bourgoin-Voillard, S.; Afonso, C.; Lesage, D.; Zins, E.-L.; Tabet, J.-C.; Armentrout, P. B. J. Am. Soc. Mass Spectrom.2013, 24, 365-380.  DOI: 10.1007/s13361‑012‑0554‑0
    1. “Threshold Collision-Induced Dissociation of Hydrated Magnesium: Experimental and Theoretical Investigation of the Binding Energies for Mg2+(H2O)x complexes (x = 2 – 10)” Carl, D. R.; Armentrout, P. B. ChemPhysChem (Special Issue: Aggregation of Small Molecules)2013, 14, 681-697. DOI: 10.1002/cphc.201200860

    2. “Metal Cation Dependence of Interactions with Amino Acids: Bond Energies of Rb+ and Cs+ to Met, Phe, Tyr, and Trp” Armentrout, P. B.; Yang, B.; Rodgers, M. T. J. Phys. Chem. B2013, 117, 3771-3781. DOI: 10.1021/jp401366g

    3. “Thermochemistry of Non-Covalent Ion-Molecule Interactions” Armentrout, P. B.; Rodgers, M. T. Adv. Mass Spectrometry 2013, 19, 47-58. ISBN: 978-4-902590-30-2
    1. “Structures of the Dehydrogenation Products of Methane Activation by 5d Transition Metal Cations” Lapoutre, V. J. F.; Redlich, B.; van der Meer, A. F. G.; Oomens, J.; Bakker, J. M. Sweeney, A.; Mookherjee, A.; Armentrout, P. B. J. Phys. Chem. A2013, 117, 4115–4126. DOI: 10.1021/jp400305k

    2. “Role of Methylation on the Thermochemistry of Alkali Metal Cation Complexes of Amino Acids: N-Methyl Proline” Mookherjee, A.; Armentrout, P. B. Int. J. Mass Spectrom. (Jennings & Scrivens Honor Issue)2013, 345–347, 109–119. DOI: 10.1016/j.ijms.2012.08.021

    3. “Quantum chemical study of the reactions between Pd+/Pt+ and H2O/H2S” Oier, L.; Matxain, J. M.; Ruipérez, F.; Ugalde, J. M.; Armentrout, P. B. Chem. Eur. J.2013, 19, 8832-8838. DOI: 10.1002/chem.201300222

    4. “The Bond Energy of ReO+: Guided Ion-Beam and Theoretical Studies of the Reaction of Re+ (7S) with O2” Armentrout, P. B. J. Chem. Phys.2013, 139, 084305. DOI: 10.1063/1.4818642

    5. “The Bond Energy of IrO+: Guided Ion-Beam and Theoretical Studies of the Reaction of Ir+(5F) with O2” Armentrout, P. B.; Li, F.-X. J. Phys. Chem. A2013, 117, 7754−7766. DOI: 10.1021/jp4063143

    6. “Activation of Methane by Os+: Guided Ion Beam and Theoretical Studies” Armentrout, P. B.; Parke, L.; Hinton, C.; Citir, M. ChemPlusChem (Memorial Issue for Detlef Schröder)2013, 78, 1157-1173. DOI: 10.1002/cplu.201300147

    7. “Guided Ion-Beam and Theoretical Studies of the Reaction of Os+ (6D) with O2: Adiabatic and Nonadiabatic Behavior” Hinton, C. S.; Citir, M.; Armentrout, P. B. Int. J. Mass Spectrom. (Memorial Issue for Detlef Schröder)2013, 354-355, 87-98. DOI: 10.1016/j.ijms.2013.05.015

    8. “Thermodynamics and Mechanism of Protonated Cysteine Decomposition: A Guided Ion Beam and Computational Study” Armentrout, P. B.; Stennett, E. M. S. J. Am. Soc. Mass Spectrom.2014, 25, 512-523.  DOI: 10.1007/s13361-013-0817-4

    9. “Metal Cation Dependence of Interactions with Amino Acids: Bond Dissociation Energies of Rb+ and Cs+ to the Acidic Amino Acids and Their Amide Derivatives” Armentrout, P. B.; Yang, B.; Rodgers, M. T. J. Phys. Chem. B, 2014, 118, 4300–4314. DOI: 10.1021/jp5001754

    10. “Gas-phase Perspective on the Thermodynamics and Kinetics of Heterogeneous Catalysis” Armentrout, P. B. Catalysis Science and Technology (Invited Perspective)2014, 4, 2741-2755. DOI: 10.1039/c4cy00435c

    11. “Theoretical Investigation and Reinterpretation of the Decomposition of Lithiated Proline and N-Methyl Proline” Mookherjee, A.; Armentrout, P. B. Int. J. Mass Spectrom. (Honor Issue for Veronica Bierbaum)2014, 370, 16-28. DOI: 10.1016/j.ijms.2014.06.012; reprinted 2015, 378, 212-224. DOI: 10.1016/j.ijms.2014.08.007

    12. “Alkali Metal Cation Interactions with 15-Crown-5 in the Gas Phase: Revisited” Armentrout, P. B.; Austin, C. A.; Rodgers, M. T. J. Phys. Chem. A(Castleman Honor Issue)2014, 118, 8088-8097. DOI: 10.1021/jp4116172

    13. “Iron Cluster – CO Bond Energies from the Kinetic Energy Dependence of the Fen+ (n = 4 – 17) + CO Association Reactions” McNary, C. P.; Armentrout, P. B. Phys. Chem. Chem. Phys. (Special Issue: Size Selected Clusters and Particles: From Physical Chemistry to Catalysis)2014, 16, 26567-26477. DOI:10.1039/c4cp02040e

    14. “Guided Ion Beam Studies of the Collision-induced Dissociation of CuOH+(H2O)n (n = 1 – 4): Comprehensive Thermodynamic Data for Copper Ion Hydration” Sweeney, A. F.; Armentrout, P. B. J. Phys. Chem. A2014, 118, 10210-10222. DOI: 10.1021/jp508962d

    15. “Guided Ion Beam and Computational Studies of the Decomposition of a Model Thiourea Protein Cross-Linker” Wang, R.; Yang, B.; Wu, R. R.; Rodgers, M. T.; Schäfer, M.; Armentrout, P. B. J. Phys. Chem. B2015, 119, 3727-3742. DOI: 10.1021/jp512997z
    16. “Fifty Years of Ion and Neutral Thermochemistry by Mass Spectrometry” Armentrout, P. B. Int. J. Mass Spectrom. (Invited Article: Mass Spectrometry Entering its Second Century: 1960’s Concepts to the Present)2015, 377, 54-63. DOI: 10.1016/j.ijms.2014.04.005
    17. “Structural Elucidation of Hydrated CuOH+ Complexes using IR Action Spectroscopy and Theoretical Modeling” Sweeney, A. F.; O’Brien, J.               T.; Williams, E. R.; Armentrout, P. B. Int. J. Mass Spectrom. (Honor Issue for Veronica Bierbaum)2015, 378, 270-280.                 DOI: 10.1016/j.ijms.2014.08.037
    1. “Activation of CH4 by Th+ as Studied by Guided Ion Beam Mass Spectrometry and Quantum Chemistry” Cox, R. M.; Armentrout, P. B.; de Jong, W. A. Inorg. Chem.2015, 54, 3584–3599. DOI: 10.1021/acs.inorgchem.5b00137

    2. “Evaluation of the Exothermicity of the Chemi-ionization Reaction Sm + O ® SmO+ + e” Cox, R. M.; Kim, J.; Armentrout, P. B.; Bartlett, J.; Van Gundy, R. A.; Heaven, M. C.; Ard, S. G.; Melko, J. J.; Shuman, N. S.; Viggiano, A. A. J. Chem. Phys.2015, 142, 134307. DOI: 10.1063/1.4916396

    3. “Hydration Enthalpies of Ba2+(H2O)x, x = 1 – 8: A Threshold Collision-Induced Dissociation and Computational Investigation” Wheeler, O. W.; Carl, D. R.; Hofstetter, T. E.; Armentrout, P. B. J. Phys. Chem. A2015, 119, 3800-3815. DOI: 10.1021/acs.jpca.5b01087

    4. “Hydrated Copper Ion Chemistry: Guided Ion Beam and Theoretical Investigation of Cu2+(H2O)n (n = 7 – 10) Complexes” Sweeney, A. F.; Armentrout, P. B. Eur. J. Mass Spectrom.(Invited Article: 20th Anniversary Issue)2015, 21, 497-516. DOI: 10.1255/ejms.1334

    5. “Structural Characterization of Gas-Phase Cysteine and Cysteine Methyl Ester Complexes with Zinc and Cadmium Dications by Infrared Multiple Photon Dissociation Spectroscopy” Coates, R. A.; McNary, C. P.; Boles, G. C.; Berden, G.; Oomens, J.; Armentrout, P. B. Phys. Chem. Chem. Phys. (Invited Article: Special Issue on Optical Spectroscopy)2015, 17, 25799-25808. DOI: 10.1039/C5CP01500F

    6. “Experimental and Theoretical Investigations of Infrared Multiple Photon Dissociation Spectra of Glutamine Complexes with Zn2+ and Cd2+” Boles, G. C.; Coates, R. A.; Berden, G.; Oomens, J.; Armentrout, P. B. J. Phys. Chem. B2015, 119, 11607–11617. DOI: 10.1021/acs.jpcb.5b06528

    1. “Reactions of Th+ + H2, D2, and HD Studied by Guided Ion Beam Tandem Mass Spectrometry and Quantum Chemical Calculations” Cox, R. M.; Armentrout, P. B.; de Jong, W. A. J. Phys. Chem. B (Bruce Garrett Festschrift)2016, 120, 1601-1614. DOI: 10.1021/acs.jpcb.5b08008

    2.   “Discriminating Properties of Metal Alkali Ions towards the Constituents of Proteins and Nucleic Acids. Conclusions from Gas-Phase and Theoretical Studies” Rodgers, M. T.; Armentrout, P. B. In Metal Ions in Life Sciences. Volume 16: The Alkali Metal Ions: Their Role for Life, Sigel, A., Sigel, H., Sigel R. K. O., Eds.; Springer: Cham, Switzerland, 2016, pp 103 – 131. DOI: 10.1007/978-3-319-21756-7_4
    1. “Activation of Carbon Dioxide by a Terminal Uranium-Nitrogen Bond in the Gas-Phase: A Demonstration of the Principle of Microscopic Reversibility” Dau, P. D.; Armentrout, P. B.; Michelini, M. C.; Gibson, J. K. Phys. Chem. Chem. Phys., 2016, 18, 7334-7340. DOI: 10.1039/C6CP00494F

    2. “Cationic Noncovalent Interactions: Energetics and Periodic Trends” Rodgers, M. T.; Armentrout, P. B. Chem. Rev. (Thematic Issue: Noncovalent Interactions)2016, 116 (9), 5642–5687. DOI: 10.1021/acs.chemrev.5b00688

    3. “Bond Energies of ThO+ and ThC+: A Guided Ion Beam and Quantum Chemical Investigation of the Reactions of Thorium Cation with O2 and CO” Cox, R. M.; Citir, M.; Armentrout, P. B.; Battey, S. R.; Peterson. K. A. J. Chem. Phys.2016, 144, 184309. DOI: 10.1063/1.4948812

    4. “Mass Spectrometric Methods for the Determination of Thermodynamic Data” Armentrout, P. B. In The Encyclopedia of Mass Spectrometry. Volume 9: Historical Perspectives, Part A: The Development of Mass Spectrometry, Nier, K. A.; Yergey, A.; Gale, P. J., Eds.; Elsevier: Amsterdam, Netherlands, 2016, pp 231 – 239. DOI: 10.1016/B978-0-08-043848-1.00036-5

    5. “Thermodynamics and Mechanisms of Protonated Asparaginyl-Glycine Decomposition” Boles, G. C.; Wu, R. R.; Rodgers, M. T.; Armentrout, P. B., J. Phys. Chem. B2016, 120, 6525−6545. DOI: 10.1021/acs.jpcb.6b03253

    6. “Zn2+ and Cd2+ Cationized Serine Complexes: Infrared Multiple Photon Dissociation Spectroscopy and Density Functional Theory Investigations” Coates, R. A.; Boles, G. C.; McNary, C. P.; Berden G.; Oomens, J.; Armentrout, P. B. Phys. Chem. Chem. Phys. 2016, 18, 22434 – 22445. DOI: 10.1039/c6cp03805k

    7. “Computational Study of Reaction Mechanisms and Thermodynamics of Protonated Triglycine Decomposition” Mookherjee, A.; Van Stipdonk, M.J.; Armentrout, P. B. J. Am. Soc. Mass Spectrom., submitted for publication.

    8. “Thermodynamics and Reaction Mechanisms of Decomposition of the Simplest Protonated Tripeptide, Triglycine: A Guided Ion Beam Study” Mookherjee, A.; Armentrout, P. B. J. Am. Soc. Mass Spectrom., submitted for publication.

    9. “Activation of Methane by Ru+: Experimental and Theoretical Studies of the Thermochemistry and Mechanism” Armentrout, P. B.; Chen, Y.-M., Int. J. Mass Spectrom. (Nico Nibbering Honor Issue) 2016, in press. DOI: 10.1016/j.ijms.2016.05.003

    10. “Methane Activation by 5d Transition Metals: Energetics, Mechanisms, and Periodic Trends” Armentrout, P. B. Chem.: Eur. J. (Invited Minireview), in press. DOI: 10.1002/chem.201602015

    11. “Activation of C-H bonds in Pt+ + xCH4 Reactions, where x = 1 – 4: Identification of the Platinum Dimethyl Cation” Wheeler, O. W.; Salem, M.; Gao, A.; Bakker, J. M.; Armentrout, P. B. J. Phys. Chem. A, in press. DOI: 10.1021/acs.jpca.6b05361

    12. “Chemi-ionization reactions of La, Pr, Tb, and Ho with atomic O and La with N2O from 200 - 450 K” Ard, S. G.; Shuman, N. S.; Martinez, O.; Armentrout, P. B.; Viggiano, A. A. J. Chem. Phys. accepted for publication.

You can contact me at

Last Updated: 8/15/16