Mathematics of Autocorrelation
- Autocorrelation of Fluorescence Intensity
- Autocorrelation Due to Isotropic 3D Translational Diffusion
- Autocorrelation Due to Isotropic 2D Translational Diffusion
- Autocorrelation Due to Multicomponent Translational Diffusion
- Autocorrelation Due to Intersystem Crossing (Triplet State)
- Autocorrelation Due to Other Phenomena
Appendices
- A Useful Integral
- Key References
FCS Classroom
Autocorrelation Due to Other Phenomena
Combining Fast Phenomena into a Correction Factor
Intersystem crossing time constants (discussed in Autocorrelation Due to Intersystem Crossing (Triplet State)) are typically in the range of microseconds. Unfortunately, there are a number of phenomena which share this domain. These include rotational diffusion rates and, if one is using photomultiplier tubes for detection, after-pulsing phenomena. As a result, and particularly when using photomultipliers, one has to view this region as part of a system correction.
To take into account all these phenomena we can rewrite the three-dimensional autocorrelation equation that includes intersystem crossing (see Autocorrelation Due to Intersystem Crossing (Triplet State)) as
Where A and τC are the correction coefficients and time constants respectively.
Additional Physical Models
See our List of FCS Equations for Various Physical Processes for autocorrelation models for additional processes.