β Scribed by Joseph Le Brech; Roger M. Leblanc; Adel F. Antippa
No coin nor oath required. For personal study only.
A molecular orbital calculation, using the "free-electron-network" method, is reported for the absorption spcctrum of chlorophyll a and the complexes chlorophyU/p-dioxane and chlorophyll/p-benzoquinone.
For chlorophyil a, our results are in good agreement with experiment and are substantially the same as those obtained by Weiss using the self-consistent molecular-orbital method. Our results seem to indicate: (i) that chlorophyll a has 26 rather than 28 z electrons, (ii) that, in a chlorophyll complex, the central magnesium atom has a coordiiation number of 6, and (ii) that the cNorophyll/benzoquinone complex has an intense absorption band centered at 713 nm. If present in vivo this complex can provide a model for the P-700 energy trap.
π SIMILAR VOLUMES
## Stimulated emission of chlorophyll -a is observed in the spectral range around 670 nm. The calculated wavelength at the threshold turns out to be shifted by 20 nm towards longer wavelengths. To clarify this discrepancy, extrinsic-loss variations at the laser as well as measurements of nonlinear
To clear up controversial results of excited-singlet (St) absorption of monomeric chlorophyll-a solutions in the red spectral range, non-linear absorption measurements were performed at h = 670 nm and evaluated in andytic and mmterical terms. A large St absorption cross section has been confirmed at