Two-photon resonances in femtosecond time-resolved four-wave mixing spectroscopy: {beta}-carotene

Journal Article · Sat Aug 07 04:00:00 EDT 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3466750· OSTI ID:21559893

Namboodiri, V; Namboodiri, M; Flachenecker, G; Materny, A ^[1]

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1. Center of Functional Materials and Nanomolecular Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany)

Femtosecond time-resolved pump-degenerate four-wave mixing (pump-DFWM) spectroscopy has been used to study the ultrafast dynamics of {beta}-carotene involving several electronic and vibrational states. An initial pump pulse, resonant with the S{sub 0}-to-S{sub 2} transition, excites the molecular system and a DFWM process, resonant with the S{sub 1}-to-S{sub n} transition, is used to probe the relaxation pathways. The transient shows a peculiar decay behavior, which is due to the contributions of resonant DFWM signal of the excited S{sub 1} state, nonresonant DFWM signal of the ground S{sub 0} state and vibrational hot S{sub 0}{sup *} state, and the two-photon resonant DFWM signal of the ground S{sub 0} state. We have used a kinetic model including all the signal contributions to successfully fit the transient. The time constants extracted are in very good agreement with the known values for {beta}-carotene. For comparison, a two-pulse pump-probe experiment was performed measuring the transient absorption at the wavelength of the DFWM experiment.

• OSTI ID: 21559893
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 5 Vol. 133; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
BOSONS
CAROTENOIDS
CHEMISTRY
COMPARATIVE EVALUATIONS
ELEMENTARY PARTICLES
ENERGY LEVELS
EQUIPMENT
EVALUATION
EXCITED STATES
FREQUENCY MIXING
GROUND STATES
HYDROCARBONS
MASSLESS PARTICLES
MULTI-PHOTON PROCESSES
ORGANIC COMPOUNDS
PHOTOCHEMISTRY
PHOTONS
PIGMENTS
PULSES
PUMPS
RELAXATION
RESOLUTION
RESONANCE
SIGNALS
SORPTION
SPECTRA
SPECTROSCOPY
TERPENES
TIME RESOLUTION
TIMING PROPERTIES
TRANSIENTS
VIBRATIONAL STATES
WAVELENGTHS