Effects of Nonpolar and Polar Solvents on the Qx and Qy Energies of Bacteriochlorophyll a and Bacteriopheophytin a
| Main Authors: | Leenawaty, Limantara, Shun, Sakamoto, Yasushi, Koyama, Hiroyoshi, Nagae |
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| Format: | Article PeerReviewed |
| Terbitan: |
Wiley
, 1997
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| Subjects: | |
| Online Access: |
http://eprints.upj.ac.id/id/eprint/80/ https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-1097.1997.tb08566.x |
Daftar Isi:
- The effects of nonpolar and polar solvents on the Qx and Qy energies of bacteriochlorophyll (BChl) a and bacteriopheophytin (BPhe) a were examined by electronic absorption spectroscopy. All of the four different energies exhibited a linear dependence on R(n) = (n2 - l)/(n2+ 2), where n is the refractive index of the solvent, in both nonpolar and polar solvents. The energy of each state of both pigments could be expressed as v = -dR(n) + e (in cm-1) where coefficient d was related to the dispersive interaction between the solute and the solvent molecules. A theory developed by Nagae showed that coefficient d originates from the quantum-mechanical fluctuation of the multipole moments of the solute, in terms of which the following characteristics of the observed d values were explained: (1) In all of the four cases of the Qx, and Qy energies of both BChl a and BPhe a, the d values for the polar solvents were smaller than those for the non-polar solvents. (2) In both nonpolar and polar solvents, the d value of BChl a was larger than that of BPhe a in the Qy energy, whereas the d value of BPhe a was larger than that of BChl a in the Qx energy. (3) The d value of the Qx energy was larger than that of the Qy, energy for either case of BChl a or BPhe a.