Member, Oregon Center for Optics

B.S., University of Wisconsin, Madison, 1979. Ph.D., University of California, Berkeley, 1985 (Robert A. Harris). Postdoctoral: Massachusetts Institute of Technology, 1985–87 (Robert Silbey). Honors and Awards: James Franck Fellow, 1987–88; Camille and Henry Dreyfus Teacher-Scholar, 1991–96; John Simon Guggenheim Memorial Foundation Fellowship, 2003-2004. At Oregon since 1995.

Research Interests

My research group works on the theory and simulation of time-resolved optical spectroscopy. Time-resolved optical spectroscopy on the ultrafast (femtosecond) timescale affords physical chemists a uniquely powerful means to probe in real time and also to influence the course of molecular processes in the gases, liquids, solid materials, and biological macromolecules. Progress in this area requires direct collaboration between theoretical and experimental investigators because the systems of interest often involve multiple electronic states, induced motion in many interatomic modes, and a complicated interplay between molecular dynamics and optical interactions. While the signals are rich and informative, they’re challenging to simulate and interpret!

We have been involved recently in developing the basic theory for wavepacket interferometry (WPI) — a form of nonlinear spectroscopy using sequences of ultrashort pulses with specified optical phase relationships — to gain direct experimental information at the level of time-dependent quantum mechanical wave functions (rather than probability densities). Our analysis indicates that it should be possible to use WPI as a form of analogue computation to experimentally determine the evolving nuclear wave function of a polyatomic molecule driven by a short laser pulse of arbitrary temporal shape. Our recent simulations of wave-packet reconstruction in the E-state of gas-phase Li2 (in which vibrations and rotations cannot be dynamically separated) clearly demonstrate the capacity of WPI to determine the state of a realistic multi-dimensional quantum mechanical system. Our theoretical work in the area of wavepacket interferometry is taking place in collaboration with the experimental research groups of Thomas Dyke and Andrew Marcus at Oregon.

We are also very excited about the prospects for applying optical control and WPI to electronic energy transfer, one of the key photophysical processes underlying biochemical energy-generation in photosynthesis. In addition to completing an analysis and simulation on the use of WPI with polarized laser pulses to reveal amplitude-level information on the coherent vibrational dynamics accompanying electronic excitation transfer, we have carried out extensive calculations on a model energy-transfer complex. Our treatment puts forward an original explanation for the previously puzzling appearance of coordinated vibrational quantum beats in parallel and perpendicular emission channels in published experimental data on time-resolved polarized emission from the bacterial photosynthetic light-harvesting complex LH-1. These findings give strong hints for strategies to control the spatial transport of electronic excitation via external laser control of intra- and inter-chromophore vibrations, which we are currently pursuing.

Another area of current activity is in the simulation of condensed phase molecular processes by means of the reduced dynamical descriptions of Redfield theory and other relaxation-theory treatments along with approximate wavepacket-based descriptions of lattice-mode dynamics. We have been able to propose, analyze, and simulate in detail a method for distance-sensitive intermolecular communication via coherent lattice waves between different types of molecular “impurities” in cryogenic matrices. The approach envisions the detection of short-pulse electronic excitation of one kind of substitutional impurity by way of time-resolved coherent anti-Stokes Raman scattering (tr-CARS) difference measurements on guest molecules of another type. The predicted difference signals show step-like switching behavior of a kind that is not usually seen in ultrafast spectroscopy. This work dovetails nicely with ongoing experimental work in the area of matrix isolation spectroscopy, which is taking place at Oregon and elsewhere.

Selected Publications:

46. J. A. Cina and Travis S. Humble, "Molecular Wavepacket Decomposition by Nonlinear Interferometry," Bull. Chem. Soc. Jpn. 75, 1135 (2002).

45. Travis S. Humble and Jeffrey A. Cina, "Molecular State Reconstruction by Nonlinear Wave Packet Interferometry," Phys. Rev. Lett. 93, 60402 (2004).

43. J. A. Cina, D. Kilin, and T. S. Humble, "Wave packet interferometry for short-time electronic energy transfer: Multidimensional optical spectroscopy in the time domain," J. Chem. Phys. 118, 46 (2003).

39. J. A. Cina, "Nonlinear wavepacket interferometry for polyatomic molecules," J. Chem. Phys. 113, 9488 (2000).

36. What Can Short-Pulse Pump-Probe Spectroscopy Tell Us About Franck-Condon Dynamics?", Y.-C. Shen and J. A. Cina, J. Chem. Phys. 110, 9793 (1999).

Additional Publications

To Contact Dr. Cina:
Phone: 541-346-4617
cina@uoregon.edu

WEBMASTER
lynde@uoregon.edu