Laser spectroscopy of the methylene blue cation in an electrostatic ion storage ring

We have performed a spectroscopic study of the methylene blue cation (MB+) stored in an electrostatic ion storage ring in Tokyo Metropolitan University. Isolated MB+ ions were extracted from an electrospray ionization source and introduced into the storage ring. An excitation spectrum of isolated MB+ was obtained from the intensity of delayed fragmentation observed for about 1 ms after laser irradiation in the visible range.