ABSTRACT
We present here the infrared absorption spectra of free-base tetraphenylporphine and its dication. Most of the allowed IR bands of porphyrin skeletal are observed in pairs due to two-fold symmetry of the free-base tetraphenylporphine. Observation of some new bands, disappearance of few bands in the IR spectrum of dication are interpreted on the basis of point group symmetry S4. Intensity change in the observed bands due to vibrational motion of the phenyl rings for dication is also explained on the basis of symmetry of dication. Sharing of electrons of the B(1u) orbitals by the two added protons are responsible for the shifts in the position of certain IR bands for dication.
Subject(s)
Porphyrins/chemistry , Models, Chemical , Molecular Structure , Spectrophotometry, Infrared , VibrationABSTRACT
We report here electronic absorption, fluorescence and resonance Raman studies of rhodamine 6G laser dye dispersed in the polymethylcyanoacrylate matrix. In the electronic absorption and fluorescence spectra of dispersed rhodamine 6G, band maxima are red shifted compared to solution. Raman spectra show some new bands. These spectral changes arise due to matrix effect and interaction between rhodamine 6G and the host material involving amine group of rhodamine.
Subject(s)
Chemistry, Physical/methods , Cyanoacrylates/chemistry , Fluorescent Dyes/chemistry , Rhodamines/chemistry , Spectrometry, Fluorescence/methods , Spectrophotometry/methods , Spectrum Analysis, Raman/methods , Coloring Agents/pharmacology , Electrons , Ethylamines/chemistry , Polymers/chemistry , Rhodamines/analysisABSTRACT
We report use of laser-generated plasmas as ultraviolet continuum sources of high shot-to-shot and long-term reproducibility suitable for photoelectric scanning measurements of absorption spectra. We have used such a source combined with a focusing geometry to obtain resonance-line-absorption profiles from a 30-cm column of hot plasma. This work also confirms and extends the photographic evidence of Carroll et al. that intense and line-free continua can be obtained from such plasmas with suitable choice of target material.
