Laser-induced fluorescence line-narrowing of C60-hydroquinone crystals

The low temperature optical spectroscopy of C60-hydroquinone (C60(HQ)3) crystals has been studied by fluorescence line-narrowing and total luminescence spectroscopy. The spectra are characterized by sharp zero-phonon lines and phonon sidebands of neutral C60. Symmetric hg and ag modes and progressions in the Jahn-Teller active 260 cm−1 hg squashing mode dominate the fluorescence spectra indicating the hexagonal environment of the crystal has distorted the C60 icosahedral symmetry. There may ae a Jahn-Teller distortion of the excited state. The line-narrowing experiments show there is substantial inhomogeneous broadening because of rotational disorder in the crystal.