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Katharine Moore Tibbetts

Education

A.B., Princeton University, 2005

Ph.D., Princeton University, 2012

Graduate Intern, Sandia National Laboratories, 2011

Postdoctoral Fellow, Temple University, 2012-2015

Honors and Awards

National Science Foundation Graduate Research Fellowship, 2006-2009.

Centennial Fellowship, Princeton University, 2006-2011.

Hubert Alyea Teaching Award, Princeton University, 2008.

Fulbright Fellowship in Germany, 2005-2006.

Research interests

The goal of my research is to investigate chemical reactions induced by strong field femtosecond laser excitation of gas- and condensed-phase molecules. The short time duration (~10-14 s) and high electric field strength (~5 V/m) of femtosecond laser pulses make them ideal for both inducing novel chemical transformations and probing reaction dynamics in real time. The unique nonequilibrium chemistry induced by femtosecond laser excitation has been shown to enable the synthesis of novel nanomaterials with desirable physical and chemical properties, but little is known about the reaction mechanisms involved. My research will focus on identifying reactive intermediates and elucidating reaction mechanisms for these transformations in the condensed phase, as well as probing and controlling the dynamics of gas phase molecular dissociation reactions.

  1. Synthesis of plasmonic nanomaterials

Synthesis of noble metal nanoparticles with tailored sizes and shapes is an active area of research because these materials have unique optical and electronic properties arising from the surface plasmon resonance phenomenon. While many chemical synthetic routes to these types of nanomaterials exist, femtosecond laser reduction of noble metal salt precursors has the advantages of avoiding the use of environmentally damaging reducing agents and organic surfactants that can limit practical use of the resulting materials. For instance, femtosecond laser irradiation can be used to synthesize “naked” gold triangular nanoplates, whose surfaces may be functionalized with ligands tailored to biomedical or other applications. Future work will focus on the size- and shape-controlled synthesis of nanoparticles of gold, silver, platinum, palladium, copper, and their alloys by (co)-reduction of aqueous metal salt solutions. The reaction progress will be monitored by in situ UV-VIS absorption spectroscopy and mass spectrometric detection of gaseous side products in order to determine the reaction mechanisms involved.

  1. Dissociation dynamics of gas phase molecules

Unimolecular dissociation reactions of excited or ionized molecules are particularly suited to in-depth investigation of reaction mechanisms using time-resolved “pump-probe” spectroscopy, which can follow molecular dissociation on its natural timescale. Mass spectrometric detection of transient ionized species, combined with quantum chemical calculations of the molecule’s electronic potential energy surfaces, has revealed which excited states are involved in the loss of a methyl group from acetophenone to form the benzoyl cation. Future work will probe dissociation reactions in related molecules by varying the wavelengths of the pump and probe pulses in order to specify which excited states are accessible upon excitation, which should enable control over the resulting dissociation products.

Selected Publications

B.Tangeysh, K. Moore Tibbetts, J. H. Odhner, B. B. Wayland, and R. J. Levis, “Triangular Gold Nanoplate Growth by Oriented Attachment of Au Seeds Generated by Strong Field Laser Reduction” Nano Lett. 15(5) 3377-3382 (2015)

S.Shumlas, K. Moore Tibbetts, J. H. Odhner, R. J. Levis, and D. R. Strongin, “Formation of Carbon Nanospheres via Ultrashort Pulse Laser Irradiation of Methane” Mater. Chem. Phys. 156 47-53 (2015)

B.Bohinski, K. Moore Tibbetts, M. Tarazkar, D. A. Romanov, S. Matsika, and R. J. Levis, “Strong Field Adiabatic Ionization Prepares a Launch State for Coherent Control” J. Phys. Chem. Lett. 5 4305-4309 (2014)

J.H. Odhner, K. Moore Tibbetts, B. Tangeysh, B. B. Wayland, and R. J. Levis, “Mechanism of Improved Au Nanoparticle Size Distributions Using Simultaneous Spatial and Temporal Focusing for Femtosecond Laser Irradiation of Aqueous KAuCl4” J. Phys. Chem. C 118(41) 23986-23995 (2014)

K. Moore Tibbetts, T. Bohinski, K. Munkerup, M. Tarazkar, and R. J. Levis, “Controlling Dissociation of Alkyl Phenyl Ketone Radical Cations in the Strong Field Regime through Hydroxyl Substitution Position” J. Phys. Chem. A 118(37) 8170-8176 (2014)

B. Bohinski, K. Moore Tibbetts, K. Munkerup, M. Tarazkar, D. A. Romanov, S. Matsika, and R. J. Levis, “Radical Cation Spectroscopy via Tunnel Ionization” Chem. Phys. 442 81-85 (2014)

K. Moore Tibbetts, X. Xing, and H. Rabitz, “Laboratory Transferability of Optimally Shaped Laser Pulses for Quantum Control” J. Chem. Phys. 140(7) 074302 (2014)

B. Tangeysh, K. Moore Tibbetts, J. H. Odhner, B. B. Wayland, and R. J. Levis, “Gold Nanoparticle Synthesis Using Spatially and Temporally Shaped Femtosecond Laser Pulses: Post-Irradiation Auto-Reduction of Aqueous [AuCl4]-” J. Phys. Chem. A 117(36) 18719-18727 (2013)

B. Bohinski, K. Moore Tibbetts, M. Tarazkar, D. Romanov, S. Matsika, and R. J. Levis, “Measurement of Ionic Resonances in Alkyl Phenyl Ketone Cations via Infrared Strong Field Mass Spectrometry” J. Phys. Chem. A 117(47) 12374-12381 (2013)

B. Bohinski, K. Moore Tibbetts, M. Tarazkar, D. Romanov, S. Matsika, and R. J. Levis, “Measurement of an Electronic Resonance in a Ground-State, Gas-Phase Acetophenone Cation via Strong-Field Mass Spectrometry” J. Phys. Chem. Lett. 4(10) 1587-1591 (2013)

K. Moore Tibbetts, X. Xing, and H. Rabitz, “Exploring Control Landscapes for Laser-Driven Molecular Fragmentation” J. Chem. Phys. 139(14) 144201 (2013)

K. Moore Tibbetts, X. Xing, and H. Rabitz, “Optimal Control with Homologous Families of Photonic Reagents and Chemical Substrates” Phys. Chem. Chem. Phys. 15(41) 18012-18022 (2013)

K. Moore Tibbetts, X. Xing, and H. Rabitz, “Systematic Trends in Photonic Reagent Induced Reactions in a Homologous Chemical Family with Ultrafast Laser Pulses” J. Phys. Chem. A 117(34) 8205-8215 (2013)

K. W. Moore, A. Pechen, X.-J. Feng, J. Dominy, V. Beltrani, and H. Rabitz, “Why is Chemical Synthesis and Property Optimization Easier than Expected?” Phys. Chem. Chem. Phys. 13(21) 10048-10070 (2011)

K. W. Moore, A. Pechen, X.-J. Feng, J. Dominy, V. Beltrani, and H. Rabitz, “Universal Characteristics of Chemical Synthesis and Property Optimization” Chem. Sci. 2(3) 417-424 (2011)