High-resolution spectroscopy of jet-cooled naphthalene:: the 000 and 3310 bands of the (A)over-tilde 1B1u←(X)over-tilde1Ag transition

Rotationally resolved excitation spectra of the 0(0)(0) and 33(0)(1) bands of the (A) over tilde B-1(1u) <-- (X) over tilde (1) A(g). electronic transition of naphthalene were measured by a frequency-doubled single-mode tunable laser and a jet-cooled collimated molecular beam. The observed linewidth was 18 MHz, and the absolute wavenumber was determined with an accuracy of better than 0.0002 cm(-1). The molecular constants of the (X) over tilde (1)A(g) (v = 0), (A) over tilde B-1(1u)(v = 0), and (A) over tilde (1) B-1u(v(33) = 1) levels were determined and represent the most accurate measurements to date. Three rotational constants were sufficient to fit 3386 lines of J = 1-43 and K-a = 0-21 with a standard deviation 0.0002 cm(-1). This indicates that the molecular structures are rigid both in the (X) over tilde (1)A(g) and (A) over tilde B-1(1u) states. When a magnetic field was applied, spectral line broadening was observed for levels with small K-a value in the (A) over tilde B-1(1u) (v(33) = 1) state, and the Zeeman splitting was observed to increase with increasing J. No broadening, however, was observed in the 0(0)(0) band up to H = 0.65 T. (C) 2002 Elsevier Science (USA).