Current Research

Our research program uses lasers, electrical discharges and pulsed supersonic molecular beams to produce a variety of unusual molecules, ions, metal complexes and atomic or molecular clusters.  The extreme conditions of the "synthesis" processes employed make it possible to produce strange molecular aggregates including metal atom nanoclusters, novel organometallic complexes (metal benzene sandwiches, metal-fullerenes), metal ions "solvated" by 1-30 water molecules, proton-bound dimers, or carbocations.  These systems test fundamental concepts of chemical bonding and provide models for metal-metal or metal-ligand bonding, metal ion solvation and metal-adsorbate interactions, and additionally provide specific examples of proton-transfer or organic reaction intermediates as well as interstellar molecules.  The ions or clusters produced are detected and size-selected with a specially-designed time-of-flight mass spectrometer and studied with UV-visible or infrared laser spectroscopy.  Computational chemistry methods are employed to complement the experimental work.  The combined spectroscopy measurements and computational work provides definitive answers about molecular structure, electronic structure, bonding energetics and the reactivity of these systems.

Selected Publications

McDonald, D. C. ; Mauney, D. T. ; Leicht, D. ; Marks, J. H. ; Tan, J. A. ; Kuo, J. - L. ; Duncan, M. A. Communication: Trapping a proton in argon: Spectroscopy and theory of the proton-bound argon dimer and its solvation. The Journal of Chemical Physics 2016, 145, 231101.
Ward, T. B. ; Carnegie, P. D. ; Duncan, M. A. Infrared spectroscopy of the Ti(H2O)Ar+ ion–molecule complex: Electronic state switching induced by argon. Chem. Phys. Lett. 2016, 654, 1 - 5.
Maner, J. A. ; Mauney, D. T. ; Duncan, M. A. Imaging Charge Transfer in a Cation−π System: Velocity-Map Imaging of Ag + (benzene) Photodissociation. J. Phys. Chem. Lett. 2015, 6, 4493 - 4498.
Brathwaite, A. D. ; Ward, T. B. ; Walters, R. S. ; Duncan, M. A. Cation−π and CH−π Interactions in the Coordination and Solvation of Cu + (acetylene) n Complexes. J. Phys. Chem. A 2015, 119, 5658 - 5667.
Mosley, J. D. ; Young, J. W. ; Huang, M. ; McCoy, A. B. ; Duncan, M. A. Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer. J. Chem. Phys. 2015, 142, 114301.
Mosley, J. D. ; Young, J. W. ; Agarwal, J. ; Schaefer, H. F. ; v. Schleyer, P. R. ; Duncan, M. A. Structural Isomerization of the Gas-Phase 2-Norbornyl Cation Revealed with Infrared Spectroscopy and Computational Chemistry. Angewandte Chemie 2014, 126, 5998 - 6001.
Luo, S. ; Dibble, C. J. ; Duncan, M. A. ; Truhlar, D. G. Ligand-Mediated Ring → Cube Transformation in a Catalytic Subnanocluster: Co 4 O 4 (MeCN) n with n = 1–6. J. Phys. Chem. Lett. 2014, 5, 2528 - 2532.
Mosley, J. D. ; Young, J. W. ; Duncan, M. A. Infrared spectroscopy of the acetyl cation and its protonated ketene isomer. J. Chem. Phys. 2014, 141, 024306.
Brathwaite, A. D. ; Maner, J. A. ; Duncan, M. A. Testing the Limits of the 18-Electron Rule: The Gas-Phase Carbonyls of Sc + and Y +. Inorg. Chem. 2014, 53, 1166 - 1169.
Bandyopadhyay, B. ; Reishus, K. N. ; Duncan, M. A. Infrared Spectroscopy of Solvation in Small Zn + (H 2 O) n Complexes. The Journal of Physical Chemistry A 2013, 117, 7794 - 7803.
Ricks, A. M. ; Brathwaite, A. D. ; Duncan, M. A. IR Spectroscopy of Gas Phase V(CO 2 ) n + Clusters: Solvation-Induced Electron Transfer and Activation of CO 2. The Journal of Physical Chemistry A 2013, 117, 11490 - 11498.
Duncan, M. A. Invited Review Article: Laser vaporization cluster sources. Rev. Sci. Instrum. 2012, 83, 041101.
Cheng, T. C. ; Bandyopadhyay, B. ; Mosley, J. D. ; Duncan, M. A. IR Spectroscopy of Protonation in Benzene–Water Nanoclusters: Hydronium, Zundel, and Eigen at a Hydrophobic Interface. Journal of the American Chemical Society 2012, 134, 13046 - 13055.
Duncan, M. A. Infrared Laser Spectroscopy of Mass-Selected Carbocations. The Journal of Physical Chemistry A 2012, 116, 11477 - 11491.
Ricks, A. M. ; Gagliardi, L. ; Duncan, M. A. Infrared Spectroscopy of Extreme Coordination: The Carbonyls of U+ and UO2+. J Am Chem Soc 2010, 132, 15905-15907.
Cheng, T. C. ; Bandyopadyay, B. ; Wang, Y. M. ; Carter, S. ; Braams, B. J. ; Bowman, J. M. ; Duncan, M. A. Shared-Proton Mode Lights up the Infrared Spectrum of Fluxional Cations H5+ and D5+. Journal of Physical Chemistry Letters 2010, 1, 758-762.
Douberly, G. E. ; Walters, R. S. ; Cui, J. ; Jordan, K. D. ; Duncan, M. A. Infrared Spectroscopy of Small Protonated Water Clusters, H+(H2O)n (n=2-5): Isomers, Argon Tagging, and Deuteration. Journal of Physical Chemistry A 2010, 114, 4570-4579.
Ricks, A. M. ; Douberly, G. E. ; Schleyer, P. V. ; Duncan, M. A. Communications: Infrared spectroscopy of gas phase C3H3+ ions: The cyclopropenyl and propargyl cations. Journal of Chemical Physics 2010, 132, 051101.
Ricks, A. M. ; Reed, Z. D. ; Duncan, M. A. Seven-Coordinate Homoleptic Metal Carbonyls in the Gas Phase. Journal of the American Chemical Society 2009, 131, 9176-+.
Ricks, A. M. ; Bakker, J. M. ; Douberly, G. E. ; Duncan, M. A. Infrared Spectroscopy and Structures of Cobalt Carbonyl Cations, Co(CO)n+ (n=1-9). Journal of Physical Chemistry A 2009, 113, 4701-4708.
Carnegie, P. D. ; McCoy, A. B. ; Duncan, M. A. IR Spectroscopy and Theory of Cu+(H2O)Ar2 and Cu+(D2O)Ar2 in the O-H (O-D) Stretching Region: Fundamentals and Combination Bands. Journal of Physical Chemistry A 2009, 113, 4849-4854.
Douberly, G. E. ; Ricks, A. M. ; Duncan, M. A. Infrared Spectroscopy of Perdeuterated Protonated Water Clusters in the Vicinity of the Clathrate Cage. Journal of Physical Chemistry A 2009, 113, 8449-8453.
Ricks, A. M. ; Douberly, G. E. ; Duncan, M. A. The Infrared Spectrum of Protonated Naphthalene and Its Relevance for the Unidentified Infrared Bands. Astrophysical Journal 2009, 702, 301-306.