Laser action and photoisomerisation of 3,3′-diethyl oxadicarbocyanine iodide (DODCI): Influence of temperature and concentration

✍ Scribed by C. Rullière

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 653 KB
• Volume: 43
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(76)85308-0

✦ Synopsis

Formation and decay rate constants of the DODCI photoisomer are found to follow an Arrhenius law with respectively an activation energy of 4.5 f 0.4 k&/M and 14 f 0.3 kcal/M. On the basis of these results a kinetic scheme is proposed for DODCI photoisomerisation. It appears from measurements of the fluorescence quantum yield variation as a function of the temperature that non-radiative transitions in DODCI are principally due to photoisomerisation. DODCI wavelength laser emission changes with the temperature showing that above -5°C laser action is due to the photoisomer and below -40°C to DODCI normaI form. Between -5°C and -40°C laser action occurs simultaneously from DODCI photoisomer and normal form at two different wavelengths. For a given excitation energy, variation of DODCI concentration is shown to induce a large change in the spectral distribution of DODCI fluorescence. This implies that an important radiative energy transfer does occur between DODCI normal form and the photoisomer.