Phase Acrobatics: The Influence of Excitonic Resonance and Gold Nonresonant Background on Heterodyne-Detected Vibrational Sum Frequency Generation Emission
| Autor: | Christopher C. Rich, Amber T. Krummel, Kathryn A. Lindberg |
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| Rok vydání: | 2017 |
| Předmět: |
Sum-frequency generation
Chemistry Exciton Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Molecular physics Spectral line 0104 chemical sciences Vibration Delocalized electron Molecular vibration General Materials Science Physics::Chemical Physics Physical and Theoretical Chemistry 0210 nano-technology Spectroscopy |
| Zdroj: | The Journal of Physical Chemistry Letters. 8:1331-1337 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.7b00277 |
| Popis: | We show how heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy can discriminate between the excitonic and monomeric properties of a helical, nanotube molecular aggregate by monitoring the phase of the VSFG emission associated with different polarization configurations. By keeping track of the “phase acrobatics” associated with the added phase of the nonresonant SFG emission of gold as well as that of the double-resonance conditions achieved when the SF frequency is resonant with an electronic exciton transition, we discover that for aggregates of tetra(sulfonatophenyl)porphyrin (TSPP) the PPP-polarized spectra exhibit double-resonance conditions while SSP-polarized spectra exhibit resonance only with the ground-state vibration. Along with observed shifts in the vibrational frequency, intensity differences, and sign flips in the imaginary second-order susceptibility, χs,Im(2), we conclude that PPP-polarized HD-VSFG spectra reflect the delocalized, excitonic nature of the molecu... |
| Databáze: | OpenAIRE |
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