Solvent effects on the UV/VIS absorption spectrum of bis-(dimethylamino)-heptamethinium chloride [(BDH)+Cl−]
✍ Scribed by T. Harder; J. Bendig
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 206 KB
- Volume
- 228
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The nature of the solvent has a small influence on the position of the longest wavelength absorption band and the oscillator strength (So-~ S l transition) of (BDH) + Cl-. A linear correlation between the molar excitation energy of (BDH) + Cl-and the refractive index function f(n) = (n 2_ 1 )/(2n 2+ l ) proves that dispersion forces are mainly responsible for the position of the longest absorption wavelength. Furthermore, the oscillator strength decreases with a rising value of the mentioned refractive index function. This means that dispersion forces cause a small disturbance of the ideal polymethine state in the first excited singlet state and lead to a decrease in the transition probability.