Pulsed laser methods are used to measure ultrafast photochemistry and energy dynamics in the condensed phase. These include tunable mid-infrared (IR) or visible/ultraviolet (UV) excitation with multichannel mid-IR or Terahertz detectors (THz) for time-resolved spectroscopy, hyperspectral imaging, and related nonlinear spectroscopies. Systems investigated include carriers in semiconductors and organic thin films, metal plasmons, photoreactions, biopolymers, and molecular vibrational energy transfer of inorganic or organic species in solution in crystals and on surfaces. Emphasis is placed on developing vibrational probes to investigate organic and protein/peptide systems, novel solar cell materials and electronic-vibrational energy transfer processes, photochemistry of organometallic “switch” compounds, and dynamics of hydrogen-bonded solution-phase complexes. We also examine polymerization and heterogeneous catalytic reactions, coherent control by chirped femtosecond IR vibrational overtone excitation of metal-carbonyls, and dissociation and recombination rates of nucleic acid base pairs, amino acids, sugars, and model biosystems.

Apparatus includes (1) two Ti:Sapphire 20 fs oscillators, each with kHz regenerative amplifiers and UV-visible IR OPAs; (2) a THz pump-probe spectrometer and imaging apparatus setup; (3) CW-modelocked, Nd+3 Vanadate system with three synch-pumped 400 fs, 20 Hz amplified dye lasers; (4) nonlinear crystals for sum, mid-IR, and THz generation; (5) CCDs and two mid-IR focal-plane arrays for multichannel detection and imaging applications; and (6) a THz Fourier transform infrared spectrometer for static spectroscopy. For more detailed information and recent publications, please see Web pages at: https://www.nist.gov/people/edwin-j-heilweil

Keywords:

Biophysics; Carrier dynamics; Condensed phase dynamics; Energy transfer; Femtosecond; Hyperspectral imaging; Infrared; Molecular dynamics; Terahertz imaging; Terahertz spectroscopy; Ultrafast lasers; Vibrational spectroscopy;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants