5, from ASTM

5, from ASTM buy FG-4592 [http://​rredc.​nrel.​gov/​solar/​spectra/​am1.​5/​]. The relative cost parameter \(C_P_\rm in/C_P_\rm in\) + C G) was 0 (black), 0.55, 0.82, 0.95, or 1 (white) Fig. 2 Growth power-optimized absorptance (1 − T) selleck chemicals spectrum as a function of cost. The spectra were obtained from transmitted power spectra like those in Fig. 1 and smoothed on a wavelength

scale by convolution with a 10 nm wide Gaussian function. Progressively lighter gray shades correspond to increasing relative costs of light-harvesting For increasing values of the relative cost, shown in progressively lighter shades, the bandgap shifts stepwise to higher energy/shorter wavelength, jumping the strong atmospheric absorption lines in the infra-red, while the spectrally constant level of transmitted power at higher photon energies

gradually increases and its intersection with the irradiance spectrum, beyond which no absorption occurs, shifts to lower photon energy/longer wavelength. As the price of light-harvesting complexes (in energy cost of synthesis per unit of integrated dipole strength) increases, PF-04929113 the relative cost approaches unity while the total amount of dipoles approaches zero, until the “single pigment” situation studied by Björn (1976) is obtained. Focusing on the spectra at high cost, Figs. 3 and 4 show that at the highest costs only in the 670–680 nm region some absorption remains, which corresponds to the position of the red absorption band of chlorophyll a in vivo. At lower costs a second band appears, close to the position of that of chlorophyll b, and the spectral shape becomes quite similar to the red absorption band of the photosynthetic apparatus, shown in gray.

Fig. 3 Detail of Fig. 1 for high costs. The solid lines represent the transmitted power spectra corresponding to relative costs of 0.934, 0.962, 0.978, 0.986 (in upward direction for increasing costs), Forskolin concentration corresponding to an increase in energy cost per dipole by a factor of 5 for each step. The dashed lines represent the same calculations performed with only 1% of the solar irradiance and multiplied by 100 to fit the same scale. The heavy gray line is the solar irradiance. For reference also the extra-terrestrial irradiance (air mass 0, from the same source [http://​rredc.​nrel.​gov/​solar/​spectra/​am0/​]) is shown Fig. 4 Detail of Fig. 2 for high costs. Absorptance spectra corresponding to the transmitted power spectra shown in Fig. 3. The gray shaded spectrum is an absorptance plot of the absorption spectrum of spinach chloroplasts, corrected for scattering and flattening (Latimer and Eubanks 1962) and arbitrarily normalized to obtain an absorptance at the red maximum corresponding to that of the most similar theoretical curve The relative costs used for calculating the solid curves in Figs.

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