Optical properties of the quasi-two-dimensional dichalcogenides 2H-TaSe2 and 2H-NbSe2 S. V. Dordevic, D. N. Basov, R. C. Dynes, B. Ruzicka, V. Vescoli, L. Degiorgi, H. Berger, R. Gaál, L. Forró and E. Bucher Eur. Phys. J. B, 33 1 (2003) 15-23 Published online: 23 May 2003 DOI: 10.1140/epjb/e2003-00136-1