B.A. magna cum laude Chemistry, Mathematics, Physics (1975) University of Minnesota
Ph.D. Chemistry (1981) University of Wisconsin
Theoretical chemistry, dissociative and surface-enhanced resonance Raman spectroscopy, four-wave-mixing spectrsocopy, wavelets in quantum mechanics and signal processing
Email: johnson@rice.edu
Phone: (713) 348-5103
Office: Space Science & Tech. Bldg., 228
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Bruce Johnson
Distinguished Faculty Fellow in Chemistry
Research Statement
Research in this group follows four main thrusts: (1) Applications of wavelets to quantum dynamics, (2) Dissociative resonance Raman spectroscopy, (3) Surface-enhanced Raman spectroscopies on metal nanoshells, and (4) Development of Pulsed Multiline Excitation DNA fluorescence technology.
Wavelet analysis provides more customizable resolution than Fourier analysis. It has been extensively used in signal and image processing, but its use in numerical analysis still needs much further work. Our research has established that systematic high accuracy can be obtained using compact support wavelets for quantum boundary/initial value problems in molecular physics. This work is funded by NSF and is leading to the development of C++ wavelet software (MultiWavePack) to collect many of the tools needed for the long-term goal of constructing highly-adaptive Schrodinger-equation solvers. Several summer visitors in the Research Experiences for Undergraduates program at the Rice Quantum Institute have participated in this research, all of them having or about to gain a publication from their projects. A graduate student in Applied Physics is maintaining the code.
The particular application that has driven the wavelet technology development stems from collaboration with James Kinsey and Carter Kittrell on Dissociative Resonance Raman Spectroscopy. It had long been thought that Raman spectroscopy was impossible in molecules that break bonds when photoexcited since the bond rupture is orders-of-magnitude faster than radiative lifetimes. The Kinsey group and others have nevertheless demonstrated in a number of polyatomic molecules that there is a small amount of Raman-scattered light that can be analyzed to obtain a unique look at the early femtoseconds of the photodissociation process. As thoroughly explained by Eric Heller and coworkers, the natural interpretation of this spectroscopy lies in solution of the time-dependent Schrodinger equation. The long Raman vibrational progressions seen in the Kinsey experiments have required, however, that large amplitude vibrations rather than low-energy normal modes be used in analyzing the spectra. The wavelet approach is currently being adapted to solution of the quantum dynamics for photodissociation of ClNO in the A electronic band, for which experimental results have already been published (NSF and Welch Foundation).
In conjunction with the groups of Naomi Halas and Peter Nordlander, multimode quantum mechanical density matrix simulations have been developed for understanding Surface-Enhanced Raman Spectroscopy (SERS) and Surface-Enhanced Raman Optical Activity (SEROA) using metal nanoshells as active substrates. The huge enhancements seen in SERS are attributable to the tremendous local fields seen near plasmonic devices like silver and gold nanoshells with dielectric cores. These are unique, however, in that the natural resonances of these nanoparticles are individually tuneable throughout the visible and near-IR regions of the spectrum by varying the core and shell radii. This area of research is in conjunction with the Laboratory for Nanophotonics (LaNP), which is funded by both NSF and DoD. The particular recent application has been to silver nanoshells coated with para-aminobenzenethiol molecules, using integration of the optical Bloch equations in a multimode model description of the SERS spectra.
A collaboration between Johnson, Carter Kittrell, Robert Curl at Rice and Michael Metzker at Baylor College of Medicine has been developing the Pulsed Multiline Excitation (PME) method to improve the currently-used fluorescent DNA sequencing technology. This method uses four compact lasers that are sequentially stepped to probe DNA strands tagged with four different fluorophores which are each optimized for a particular laser frequency. This method is designed to eliminate cross-talk between different A, C, T, G channels and to decrease error rates and collection times in large-scale genome sequencing. This work was published in 2005.
Selected Publications
D. W. Massey, R. Acevedo and B. R. Johnson "Additions to the class of symmetric-antisymmetric multiwavelets: Derivation and use as quantum basis functions." J. Chem. Phys., 124 (2006): 014101.
S. W. Bishnoi, C. J. Rozell, C. S. Levin, M. K. Gheith, B. R. Johnson, D. H. Johnson and N. J. Halas "All-Optical Nanoscale pH Meter." NanoLetters, 6 (2006): 1687-1692.
J. W. Gibson and B. R. Johnson "Density matrix calculation of surface enhanced Raman scattering for p-mercaptoaniline on silver nanoshells." J. Chem. Phys., 124 (2006): 064701.
C. D. Griffin, R. Acevedo, D. W. Massey, J. L. Kinsey and B. R. Johnson "Multimode wavelet basis calculations via the molecular self-consistent-field plus configuration-interaction method." J. Chem. Phys., 124 (2006): 134105.
D. K. Sparks and B. R. Johnson "Two-dimensional quantum propagation using wavelets in space and time." J. Chem. Phys., 125 (2006): 114104.
E. K. Lewis, W. C. Haaland, F. Nguyen, D. A. Heller, M. J. Allen, R. R. MacGregor, C. S. Berger, B. Willingham, L. A. Burns, G. B. I. Scott, C. Kittrell, B. R. Johnson, R. F. Curl and M. L. Metzker "Color Blind Fluorescence Detection for Four-Color DNA Sequencing." Proc. Natl. Acad. Sci., 102 (2005): 5346-5351.
H. Wang, R. Acevedo, H. Molle, J. L. Mackey, J. L. Kinsey and B. R. Johnson "Multiscale quantum propagation using compact support wavelets in space and time." J. Chem. Phys., 121 (2004): 7647-7657.
Thierry A. Wasserman, Patrick H. Vaccaro, Johnson, B. "The influence of finite bandwidth excitation sources in degenerate four-wave mixing spectroscopy." J. Chem. Phys., 116 (2002): 10099-10121.
A. Maloney, Kinsey, J., Johnson, B. "Wavelets in curvilinear coordinate quantum calculations: H2+ electronic states." J. Chem. Phys., 117 (2002): 3548-3557.
Presentations
"Density matrix calculation of surface enhanced Raman scattering for p-mercaptoaniline on silver nanoshells." Nanoscience Workshop at the University of Arkansas Little Rock, University of Arkansas Little Rock. (May 2006) With J. W. Gibson.
PI. "Multiscale Quantum Propagation Using Compact Support Wavelets in Space and Time,." Telluride Symposium on Dynamics and Many Body Theory, Telluride, CO. (August 2004) With H. Wang, R. Acevedo, H. Molle, J. L. Mackey, J. L. Kinsey and B. R. Johnson.
PI. "Mixed Time-Frequency Quantum Propagation Using Compact Support Wavelets,." American Mathematical Society, Athens, OH (USA). (March 2004) With H. Wang, R. Acevedo, H. Molle, J. L. Mackey, J. L. Kinsey and B. R. Johnson.
"Wavelet Basis Calculation of Wannier Functions." 225th American Chemical Society National Meeting, New Orleans, LA. (Mar, 2003) With Stephen D. Clow.
"Wavelet Solution of the Schr¿dinger Equation." Department of Chemistry, Division of Physical Chemistry, Texas Technology University, Lubbock, TX. (Feb, 2003)
Theses
Joshua Gibson, MS, Physics. "Density Matrix Calculation of Surface Enhanced Raman Scattering for Silver Nanoshells Coated with p-Mercaptoaniline." (2005).(Thesis or Dissertation Director)
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