Measuring the Spectral Diffusion of Chlorophyll a Using Two-Dimensional Electronic Spectroscopy

Kym Wells (1) , Zhengyang Zhang (1) , Jérémy Rouxel (2, 1) , Howe-Siang Tan (1)

1 Nanyang Technological University [Singapour]
2 LNIO - Laboratoire de Nanotechnologie et d'Instrumentation Optique

Ultrafast two-dimensional electronic spectroscopy has been used to study the spectral diffusion of the Qy transition of chlorophyll a in methanol. The two time frequency-fluctuation correlation function (FFCF) of the transition has been measured using the center line slope method, together with optimized fitting of the linear spectrum. The FFCF was measured to decay over four time scales. The three fastest time constants of which were measured to be ∼65 fs, ∼0.5 ps, and ∼7 ps. These are assigned as the inertial component of solvation and spectrally diffusive solvation processes respectively. The fourth time constant (>1 ns) may be attributed to the chromophore structural inhomogeneity.

Domains: Chemical Physics [physics.chem-ph]

Kym Wells, Zhengyang Zhang, Jérémy Rouxel, Howe-Siang Tan. Measuring the Spectral Diffusion of Chlorophyll a Using Two-Dimensional Electronic Spectroscopy. Journal of Physical Chemistry B, 2013, 117 (8), pp.2294-2299. ⟨10.1021/jp310154y⟩. ⟨hal-02382552⟩