J.M. Esteva

Low resolution VUV absorption spectrum of boron monoxide

The absorption spectrum of BO has been recorded between 2400 and 300 Å on the SA61 beam line of SUPERACO in Orsay. A new electronic transition has been observed and vibrationally analysed. Nine Rydberg states have been observed and classified into Rydberg series giving two ionization limits at 12.849eV for the X 1Σ+ ionic state and at 13.117eV for the A 1II state of BO+. Two ionization limits have been observed at 754 and 374 Å. The first of these corresponds to the B 1Σ+ state and the last one to the C 1Σ+ state of BO+. The new results are compared with the ab initio calculations of Karna and Grein concerning BO and BO+. The agreement is satisfactory.

Comparative efficiency of natural crystals and multilayers as dispersing devices in the copper L(2,3) range.

Recent sputtering techniques have been used to produce layered synthetic microstructures (LSMs) as dispersing devices for varied applications in x-ray optics and spectroscopy. These analyzers, specially suited for synchrotron radiation, have been mounted in a two-parallel crystal monochromator. In this paper we show the first experimental results obtained with beryl crystals and multilayers for analyzing x-ray spectral distributions transmitted through screens or reflected on mirrors of copper near the L(2) and L(3) absorption edges. The significance of these findings is discussed in terms of comparison with natural and synthetic crystals and of designing a useful dispersing device for x-ray spectroscopy.

The absorption spectrum of diatomic calcium between 120 and 20 nm

The vacuum ultraviolet absorption spectrum of Ca2 has been extended down to 20 nm by using the same techniques as those described by Nzohabonayo et al. [2003, Molec. Phys., 101, 2917]. All the new states observed are Rydberg states giving three new ionization limits at 13.76 eV, 17.99 eV and a third one higher than 33 eV.

The vacuum ultraviolet absorption spectrum of diatomic calcium

Calcium granules (99.5%) have been heated to 615°C in a tantalum furnace and the absorption spectrum has been observed on the SA 61 beam line of SUFERACO (Orsay) using a 3-metre Balzers monochromator down to the -LiF cut-off (1015 Å). An intense Rydberg series has been observed between 1900 and 1500 Å. This series extends from n = 5 to n = 12 and gives the ionization potential at 63068 cm−1 (1585.6 Å) or 7.819eV and the quantum defect δ = 1.73.