No abstract

High resolution absorption spectra of the A 3Π1u–X 1Σ+g system of I2, consisting of some 9552 lines of some 79 bands spanning the vibrational range v′=0–35 and v″=3–17, have been recorded and analyzed. A fit to them which uses the previously determined accurate molecular constants for the X 1Σ+g state yields an accurate new set of molecular constants for the A state, including the Λ doubling constants. The A-state vibrational and inertial rotational constants, as well as mechanically consistent centrifugal distortion constants, are represented by near-dissociation expansions, yielding an accurate representation of the experimental data which also provides a reliable global representation of all observed and unobserved vibration–rotation levels of this state.

The spectrum of neodymium excited by a sliding spark source was photographed on two vacuum ultraviolet normal-incidence spectrographs. About 250 lines attributed to Nd V, hitherto unknown, have been identified. The analysis of this spectrum established all the energy levels of the configurations 4f2, 4f5d, 4f6s and 4f6p (except for 4f2 1S0). Altogether, 48 known levels classify about 160 lines. Their theoretical calculation includes a least-squares fit with an rms error of 28 cm−1 for the even-parity levels and 26 cm−1 for the odd-parity ones, as well as the best values for relevant radial interaction parameters. In particular, interactions with the core-excited configurations 5p54f3 and 5p54f25d are discussed. Intensities derived from phosphor image plates are used to estimate an effective temperature in the spark of Teff=3.6 eV.

2014 L'analyse du spectre d'absorption de la molécule de brome représenté par le système (B-X ) Br2 et enregistré par spectroscopie par Transformée de Fourier est présentée. On montre que les 80 000 transitions enregistrées couvrant le domaine 11600-19 577 cm-1 et publiées sous forme d'un atlas peuvent être recalculées au moyen de 39 constantes : 38 étant les coefficients de Dunham servant à décrire les constantes vibrationnelles et rotationnelles des états X jusqu'à 03BD" = 14 et de l'état B jusqu'à v' = 52 (niveau situé à 5,3 cm-1 de la limite de dissociation) plus un coefficient empirique permettant de tenir compte des constantes de distorsions négligées (supérieures à M03BD). L'erreur quadratique moyenne entre les nombres d'ondes recalculés et mesurés est trouvée égale à 0,0016 cm-1 en accord avec l'incertitude estimée des mesures expérimentales.Abstract. 2014 An in extenso analysis of the (B-X ) Br2 bromine absorption spectrum recorded by means of Fourier Transform Spectroscopy is presented. It is shown that the 80 000 recorded transitions covering the 11600-19 577 cm-1 range and published in an atlas form may be recalculated by means of only 39 constants : 38 are Dunham coefficients describing the vibrational and rotational constants of both X state (up to 03BD" = 14) and B state (up to 03BD' = 52, situated only at 5.3 cm-1 from the dissociation limit of the B state), and one empirical scaling factor which takes account of neglected centrifugal constants higher than M03BD. The overall standard error between computed and measured wavenumbers is equal to 0.0016 cm-1 in agreement with the experimental uncertainties.