The resonance ionization laser ion source (RILIS) produces beams for the majority of experiments at the ISOLDE on-line isotope separator. A substantial improvement in RILIS performance has been achieved through a series of upgrade steps: replacement of the copper vapor lasers by a Nd:YAG laser; replacement of the old homemade dye lasers by new commercial dye lasers; installation of a complementary Ti:Sapphire laser system. The combined dye and Ti:Sapphire laser system with harmonics is capable of generating beams at any wavelength in the range of 210-950 nm. In total, isotopes of 31 different elements have been selectively laser-ionized and separated at ISOLDE, including recently developed beams of samarium, praseodymium, polonium, and astatine.

A high-resolution near infrared spectrum of the CrCl radical has been recorded in thermal emission with Fourier transform techniques in the interval from 6 900 cm−1 to 11 500 cm−1. Two dominating band systems have been found in this region; (1) The A 6Σ+→X 6Σ+ system, analyzed in the present work, consisting of the (0,0), (0,1), (1,0), (2,0), and (3,0) bands, the (0,0) band being located at around 9450 cm−1; (2) the B 6Π→X 6Σ+ system, with a band interpreted as (0,0), located between 8700 cm−1 and 9000 cm−1, overlapping the (0,1) band of the A 6Σ→X 6Σ+ system. A rotational analysis of the A 6Σ+→X 6Σ+ system has been carried out, and the following principal parameters (cm−1) have been derived: X 6Σ+: ωe=396.6621, Be=0.167 587 3, De=1.1835⋅10−7; A 6Σ+: ωe=379.39, Be=0.156 51. Local perturbations in the A 6Σ+ (v=0,1) levels have been attributed to interactions with the B 6Π (v=1,2) levels. In the present work, we have constrained the investigations on the B 6Π→X 6Σ+ system to the verification that the lower state is indeed X 6Σ+. This verification has been achieved through successful matchings of branches in that system to known combination differences of X 6Σ+. The assignment of the upper state as B 6Π is based on the characteristic appearance of the band. Ligand field and density functional calculations have been performed on CrF and CrCl. The results from these calculations indicate that the approximate structure of the B 6Π and 1 6Δ excited states of CrF and CrCl is Cr+[3d44s(6D)]X−, while for the X 6Σ+ ground state in both molecules it is Cr+[3d44s(6D)∼3d5(6S)]X−. A combined DFT/LFT treatment has been carried out on the Cr+ 3d5and 3d44s configurations of both molecules in order to calculate the location of the A 6Σ+ state and of a number of low-lying states in the quartet manifold.

We report on recent near-IR observations of V4332 Sgr -the nova-like variable that erupted in 1994. Its rapid, post-outburst evolution to a cool M type giant/supergiant, soon after its outburst, had showed that it was an unusual object differing from other eruptive variables like classical/symbiotic novae or born-again AGB stars. The present study of V4332 Sgr was motivated by the keen interest in the recent eruption of V838 Mon -an object with a spectacular light-echo and which, along with V4332 Sgr, is believed to belong to a new class of objects (we propose they may be called "quasi-novae"). Our observations show new developments in the evolution of V4332 Sgr. The most striking feature is the detection of several molecular bands of AlO -a rarely seen molecule

No abstract

A survey of the jet-cooled Nb12C and Nb13C radicals has been carried out between 13 500 and 18 000 cm−1 using laser-induced fluorescence and resonant two-photon ionization spectroscopy. Several vibronic bands belonging to at least six band systems have been identified. Three of these systems appear to belong to 2Π1/2–2Δ3/2 transitions in which the lower 2Δ3/2 state is the ground electronic state of the molecule. The other three systems also terminate to the same three 2Π1/2 upper states, but originate from a state lying 830 cm−1 above the X 2Δ3/2 state. This state is assigned as the A 2Σ+ state. The ionization potential has been determined to be 56 402±15 cm−1 or 6.9929±0.0018 eV using two-color photoionization efficiency spectroscopy. This value, combined with the ionization potential of Nb and the bond energy of NbC+, yields an improved bond energy of 5.39±0.15 eV for NbC. The (4,0) band of the B 2Π1/2–X 2Δ3/2 system has been studied at a resolution of approximately 0.005 cm−1 using laser-induced fluorescence spectroscopy. The nuclear magnetic hyperfine structure has been resolved in both states, and an analysis confirms that the 2Δ ground state arises from the σ2δ1 electron configuration in which the unpaired δ electron is a pure Nb 4d electron associated with the 4F term arising from the excited 5s24d3 electron configuration. Density functional calculations have been carried out on the lowest 2Δ, 2Σ+, 4Δ, 2Π, and 4(Π,Φ) states of the neutral and the 1Σ+, 3Δ, and 3(Π,Φ) states of the cations. These calculations fully support the experimental evidence for the ground state.