A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Leninskie Gory, MGU1S40, Moscow, Russia.
J Phys Chem B. 2009 Aug 27;113(34):11720-3. doi: 10.1021/jp906565m.
We applied two-photon fluorescence excitation spectroscopy to LH2 complex from purple bacteria Allochromatium minutissimum and Rhodobacter sphaeroides . Bacteriochlorophyll fluorescence was measured under two-photon excitation of the samples within the 1200-1500 nm region. Spectra were obtained for both carotenoid-containing and -depleted complexes of each bacterium to allow their direct comparison. The depletion of carotenoids did not alter the two-photon excitation spectra of either bacteria. The spectra featured a wide excitation band around 1350 nm (2x675 nm, 14,800 cm(-1)) which strongly resembled two-photon fluorescence excitation spectra of similar complexes published by other authors. We consider obtained experimental data to be evidence of direct two-photon excitation of bacteriochlorophyll excitonic states in this spectral region.
我们应用双光子荧光激发光谱学研究了来自紫色细菌 Allochromatium minutissimum 和 Rhodobacter sphaeroides 的 LH2 复合物。在 1200-1500nm 区域内对样品进行双光子激发，测量细菌叶绿素荧光。为每种细菌的含类胡萝卜素和不含类胡萝卜素的复合物获得了光谱，以便直接进行比较。类胡萝卜素的耗尽并没有改变两种细菌的双光子激发光谱。光谱在 1350nm 左右呈现出一个宽的激发带（2x675nm，14800cm-1），强烈类似于其他作者发表的类似复合物的双光子荧光激发光谱。我们认为获得的实验数据证明了在该光谱区域中细菌叶绿素激子态的直接双光子激发。
