Light collection, problems

In an effort to carry the success of 29 forward from homogeneous solution [77] to films, the team at Miami has turned to 31 [78], While 31 forms excellent monolayer films at the air-water interface, decent anthracenic fluorescence signatures are not produced until the films are diluted substantially with stearic acid and deposited onto hydrophobic glass. As may be anticipated, neat films of 31 only show broad excimeric emissions. Light collection problems dog the experiments on the films on water. No sensitivity of the emission towards pH is found, so experiments with saxitoxin are not reported at this stage. We note the closely related PET system 32 which shows good sensing of membrane-bounded protons in micellar media [79],... 

The chloroplast contains the thyllakoid membranes in both appressed (stacked) and unappressed format. The ATPase is oriented in the membrane so that ATP synthesis is always exposed to the stromal compartment. LHCII and PSII are richly concentrated in the appressed regions to maximize light collection and electron transfer. PSI, which should not receive its excitation energy directly from PSII, is physically separated from it in the unappressed regions. Electron replacement of PSI and PSII is mediated by mobile carriers so physical separadon is not a problem. 

Also called artefacts, spurious scattering differences are arguably the biggest and best discussed nuisance in ROA spectroscopy. They can easily be understood and appreciated without any elaborate theoretical treatment, and the two optical solutions to the problem discussed in the section on light collection optics are based on simple practical considerations. 

The advantage of Raman spectromicroscopy is that very small specimens can be studied while still allowing the determination of the second and fourth moments of the ODF. However, the expressions for the Raman intensities are more complex since the optical effects induced by the microscope objective have to be considered. Although the corrections may be small, they are not necessarily negligible [59]. This problem was first treated by Turrell [59-61] and later by Sourisseau and coworkers [5]. Turrell has mathematically quantified the depolarization of the incident electric field in the focal plane of the objective and the collection efficiency of the scattered light by high numerical aperture objectives. For brevity, only the main results of the calculations will be presented. Readers interested in more details are referred to book chapters and reviews of Turrell or Sourisseau [5,59,61]. The intensity in Raman spectromicroscopy is given by [59-61]... 

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