Cut off wavelength definition for light absorption
This leads to (3)where the subscript mol now is omitted. Therefore, eq 2 is divided by Avogadro’s number N A, which is the number of molecules/mol with units mol –1.
Cut off wavelength definition for light absorption free#
Free energy is a macroscopic concept, and that remains the case, but the model is written on a molecular scale. Also, μ mol 0 is the free energy per mol of substance at temperature T = 0. The chemical potential of a substance in a dilute solution like chlorophyll with concentration mol/L usually is approximated by (see Appendix in Blankenship (1)) (2)Here, T is the absolute temperature, and R is the universal gas constant in units J K –1 mol –1. The rate by which this state eventually returns to Chl* is indicated by k b here, the subscript b refers to “back”. The two decay times mentioned correspond to rates k st = 30 × 10 9 s –1 and k st = 7 × 10 9 s –1 for the average we use the round-off value of k st = 20 × 10 9 s –1. The rate by which the product state is reached is indicated by k st, where the subscript st obviously means “storage”. Therefore, the relaxation and the subsequent decay and formation of the product state may be considered to be independent. The decay of the lowest “red” level takes place in about 33 ps for PS1 (10) and about 150 ps for PS2, (11) in both cases mainly to the product state P, considerably longer than the relaxation time of 1 ps for going to this state. The loss rate may be estimated from the fluorescence lifetime (8, 9) of about 4 ns as k l ≈ 0.25 × 10 9 s –1. For the lowest “red” level there are two possibilities: it may return to the ground state with a rate k l (the subscript l means “loss”) or it may, by many intermediate steps, go to a product state P.