[show abstract][hide abstract] ABSTRACT: We have recorded laser excitation spectra of transitions from the ground X(1)Sigma(+) state of gaseous gold fluoride (AuF) into three excited electronic states in the visible region. We prepared the sample in a dc electric discharge by flowing a dilute mixture of SF(6) in argon through a hollow gold cathode. Two of these electronic states give rise to the previously reported yellow bands of the molecule, for which a rotational analysis is given here for the first time. We have analyzed the (0,0), (1,1), (0,1), and (1,2) bands of these two transitions, which we identify as [17.8]0(+)-X(1)Sigma(+) and [17.7]1-X(1)Sigma(+); their red-degraded (0,0) band heads lie at 563.0 and 566.2 nm, respectively. The (0,0) band of a new, red-degraded [14.0]1-X(1)Sigma(+) transition at 715.1 nm has also been recorded and analyzed. An accurate set of molecular constants of the three excited states as well as the ground state has been determined by least-squares fitting all of the optical data together with measurements made by other workers of the pure rotational spectrum of AuF in its ground state. These constants include the electronic term energies, vibrational frequencies, rotational constants, and Omega-doubling constants. We discuss the nature of these three excited electronic states in terms of the ionic Au(+)F(-) electronic configurations from which they are derived.
The Journal of Physical Chemistry A 04/2010; 114(14):4831-4. · 2.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: The [17.7]1-X(1)Sigma(+) (0,0) band of AuF at 566 nm has been studied by laser excitation spectroscopy. The molecule was prepared in a dc electric discharge by flowing a dilute mixture of SF(6) in argon through a hollow gold cathode. The rotational structure of the band has been analyzed for the first time, yielding accurate values for the rotational and Omega-type doubling constants of the upper state. Hyperfine splittings arising from both the (197)Au and (19)F nuclei have been resolved by recording the spectrum at sub-Doppler resolution using the technique of intermodulated fluorescence spectroscopy. The hyperfine structure is dominated by the (197)Au magnetic dipole interaction in the [17.7]1 state, with the (197)Au magnetic hyperfine constant determined to be h(1) = -543(4) MHz. It is demonstrated that the negative value of this constant implies that the [17.7]1 state has significant (3)Delta(1) character and that spin-orbit mixing with a (1)Pi(1) state may be providing the transition intensity to the ground electronic state.
The Journal of Physical Chemistry A 11/2009; 113(47):13428-35. · 2.77 Impact Factor