Berlin 2001 – scientific programme

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MO: Molekülphysik

MO 12: Posters Friday: Spectroscopy

MO 12.16: Poster

Friday, April 6, 2001, 12:30–15:00, AT3

Spectroscopic characterization of coumarins in sol–gel – A potential laser material — •Asma Farooqui and Zahid Zaidi — Dept. of Physics, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India

Coumarins is a class of laser dyes emitting in the blue–green region of spectrum. Efficient and stable lasing dyes emitting around 480 nm are of interest for dye laser sources to be used in underwater experiments. Coumarin 480 and coumarin 460 are derived from coumarin – the parent. They lase around 460–480 nm. These dyes doped in inorganic silica alcoxide sol–gel matrix constitutes solid state organic laser material and includes all the properties of a dye laser and also offers improved stability and increased efficiency. The spectral predictions, made by us supported by theoretical results decides that sol–gel silica doped with these coumarins constitutes potential laser material. An attempt is made to study the spectroscopic characteristics of coumarin 480 and coumarin 460 molecules. Electronic absorption spectra of these coumarins are investigated in the wavelength region 200–700 nm in liquid solvents and sol–gel matrix along with fluorescence. Electronic transitions observed experimentally, are interpreted using the optimized geometries and CNDO/S–CI method.