Data for Wavelength Dependence of Plasmon-Induced Vibrational Energy Transfer in Fluorophore–Plasmonic Systems

Understanding, predicting, and controlling plasmon–molecule energy transfer are important for improvements to plasmonic photocatalysis and photothermal therapies. Here, we use continuous wave surface-enhanced anti-Stokes and Stokes Raman spectroscopy to quantify the vibrational kinetic energy, equivalent to a molecular temperature under a Boltzmann approximation, of Raman-active vibrational modes of molecules at plasmonic interfaces. In previous work from our group, we observed an anomalous steady-state reduction in vibrational kinetic energies in benzenethiols absorbed onto the surface of gold nanoparticles. To further explore this effect, here, we quantify the wavelength dependence of vibrational energy in plasmon–fluorophore systems, where molecules can undergo electronic transitions with resonant excitation. We used three excitation wavelengths and three molecules with varying electronic resonance energies. We observe wavelength-dependent vibrational energy distributions, which we attribute to competing effects of on-resonance heating and off-resonance decrease in the population ratio. This work thus quantifies the resonance wavelength dependence of vibrational energy in plasmon molecular systems and helps to suggest future applications of tailored systems with controllable energy transfer pathways.