Generalized oscillator strength for the 1B2u←1Ag transition and the observation of forbidden processes at the C 1s spectrum of the naphthalene molecule

The angular dependence of the valence and carbon is excitation in the naphthalene molecule has been studied using the electron energy-loss technique. The valence shell spectra were measured at 1.0 keV incident energy, 0-50 eV excitation energy range and in the 1.25-12.0 degrees angular range. The energy resolution was 1.0 eV (full-width at half-maximum (FWHM)). Absolute values were determined, for the first time, for the elastic differential cross section and for the generalized oscillator strength (GOS) and inelastic differential cross section for the B-1(2u)<--(1)A(g) transition (5.9 eV). The carbon is spectrum (270-330 eV) was also measured, at 1.3 keV and at an energy resolution of approximately 1.0 eV (FWHM). Dipole-forbidden processes have been observed, both at the valence and C is excitation spectra. In the latter case, a previously unreported, dipole forbidden transition, has been observed at 290.3 eV. (C) 2002 Elsevier Science B V All rights reserved.