J. Phys. Chem. Lett., 2010, 1,

Introduction Electron transfer (ET) processes and charge transfer (CT) states are involved in photosynthesis utilized in opto-electronic devices Electron donor acceptor (DA) molecules are useful for studying fundamental processes associated with electron transfer reactions CT states can be a mixture of locally excited (LE) and radical ion pair (RP; D + -A - ) states Controlled by solvent polarity DMJ-An is an example Methyl groups inhibit rotation and simplify photophysics Femtosecond Stimulated Raman Spectroscopy (FSRS) to probe the extent of charge separation in the CT state. 3,5-dimethyl-4-(9-anthracenyl)julolidine (DMJ) (An)

FSRS: Basic Principles Rev. Sci. Instrum., Vol. 75, No. 11, 2004, Annu. Rev. Phys. Chem., 2007, 58, 461 – 88.

LASER system and Experimental Setup

Annu. Rev. Phys. Chem., 2007, 58, 461 – 88. FSRS: Advantages

FSRS: Fluorescence Rejection

DMJ-An: Electronic Spectroscopy ex = 400 nm An - DMJ + DMJ-An CT Sim An 3,5-dimethyl-4-(9-anthracenyl)julolidine Room Temperature Spectra in THF, λ ex (TA) = 400 nm

FSRS Spectrum (λ ex = 400 nm, λ Raman = 800 nm, Room Temperature, THF) Anthracene localized vibrations (*) Resonance enhancement Julolidine localized vibrations (*) Compare to 9-phenylanthracene (PA) PA contains localized An Vibrations DMJ-An CT excited state most closely resembles the PA - radical anion * * * * * * * * * * * DMJ-An: FSRS Results

FSRS: Basic Principles Rev. Sci. Instrum., Vol. 75, No. 11, 2004,

Figure 1. Schematic layout of a grating-based compressor with negative dispersion, i.e. the short wavelengths (in blue) come out first.

Coherent Anti-stokes Raman Spectroscopy Increases the intensity of the anti-stokes transitions relative to spontaneous anit-stokes radiation

IR Vibrational Echo Experiments