consider a hypothetical molecule with a natural lifetime of 5 ns, and a fluorescence lifetime of 2 ns. the molecule has an absorption cross section of 8.0 x 10-15 cm2/ molecule and an emission wavelength of 575 nm. determine the localization precision possible for this molecule if imaged using 1 second frame exposures. the molecule is excited by 500 nw of 532 nm light, using a microscope equipped with a 1.25-na objective. the microscope has an overall quantum efficiency of 4%. the imaging detector has pixel dimensions of 16 micron x 16 micron. the value of b (background noise) is estimated in photons/second, at a value of 0.1 % of the photon detection rate (photons/second).