Influence of surplus negative charge on absorption and fluorescence excitation spectra of asymmetric polymethine dyes - V. I. Borysyuk; V. M. Yashchuk; A. P. Naumenko; A. V. Stanova; V. G. Gerasova; A. O. Gerasov; Yu. P. Kovtun; M. P. Shandura; O. D. Kachkovsky (Ukrainian journal of physics, 2015)