Quantum yield and image contrast of bacteriochlorophyll monolayers in photoelectron microscopy.
The photoelectron quantum yield spectrum of bacteriochlorophyll aGg (Bchl a ) from Rhodospirillum rubrum was determined in order to evaluate the possibility of mapping photoreceptor distribution and organization in bacterial chromatophores. The quantum yield is on the order of 1 X 10(-3) electrons/incident photon at 180 nm and decreases to 2.5 X 10(-5) electrons/incident photon at 230 nm. Photoelectron micrographs confirm the high contrast predicted between monolayers of Bchl a against a lipid background (calcium arachidate). A significant contrast difference is found between the two monolayer orientations, demonstrating that photoelectron microscopy is a sensitive detector of asymmetry in Bch1 a monolayers.
D001429:Bacteriochlorophylls; D002734:Chlorophyll / Q000031:analogs & derivatives; D008567:Membranes, Artificial; D008854:Microscopy, Electron; D008968:Molecular Conformation; D011789:Quantum Theory
D001429:Bacteriochlorophylls; D008567:Membranes, Artificial; D002734:Chlorophyll