Differences

This shows you the differences between two versions of the page.

--- howto:using_the_anisotropy_image_script [2018/04/12 09:39] – [Select a file and start the script] doerr
+++ howto:using_the_anisotropy_image_script [2018/04/12 10:26] – [Select a file and start the script] doerr
@@ Line 48: / Line 48: @@
   - **Left:** Imaging analysis and processing options.
   - **Upper center:** Fluorescence intensity image, displayed in false color scale. The perpendicular and parallel  fluorescence intensities measured with the two detectors are displayed in green (perpendicular) and red (parallel).
-  - **Upper right:** Fluorescence anisotropy image. By default, the rainbow color scale is spread between -0.4 and 1 (for single molecules and aligned molecules the anisotropy can vary between -0.5 and 1). When measuring a randomly aligned ensemble with parallel excitation and emission dipole moments, the anisotropy values can theoretically spread between 0 (very fast rotation or extremely efficient HOMO-FRET) and 0.4 (rotation significantly slower than the fluorescence lifetime, no HOMO-FRET).
+  - **Upper right:** Fluorescence anisotropy image. By default, the rainbow color scale is spread between -0.4 and 1.
   - **Lower graph:** Anisotropy histogram over the different pixels.
+Note:
+ The anisotropy values can theoretically spread between -0.5 and 1 for parallel or vertical excitation and emission dipoles respectively. The anisotropy value of 0 is expected in case of very fast rotation or extremely efficient energy transfer processes  (e.g. efficient  HOMO-FRET).  When measuring a randomly aligned ensemble due to photoselection the anisotropy varies with in the limits of  -0.2 and 0.4 instead of -0.5 and 1.
 ==== Adapt the script to the image and the system parameters ====