Rhodamine 101 chloride (Rhodamine 640 chloride) is a bright fluorescent dye with excitation and emission maxima of 565 and 595 nm, respectively[1].
[1]. Aigner, D., et al. New fluorescent perylene bisimide indicators--a platform for broadband pH optodes. Anal. Bioanal. Chem. 400(8), 2475-2485 (2011). [2]. Crissman, H.A., et al. Rapid, one step staining procedures for analysis of cellular DNA and protein by single and dual laser flow cytometry. Cytometry 3(2), 84-90 (1982).