QUANTITATIVE-ANALYSIS OF THE SODIUM 1S SINGLE-EXCITATION AND DOUBLE-EXCITATION SPECTRUM BY USING ATOMIC PROFILES CONVOLVED WITH THE INSTRUMENTAL FUNCTION

We give an analytical estimate of the function representing the convol ution of the Beutler-Fano profile and a Gaussian, assumed to be respon sible for the instrumental response function. From the fitting of the single-excitation spectrum, we estimate the limits of this assumption. Our formula is useful for curve fitting the experimental spectra, as it is demonstrated by the fitting of the autoionizing resonances of th e K-shell spectrum of atomic sodium. The results of the reconstruction of the spectrum provide some new data for the theoretical model. We c an point out (i) the existence of a (3p3d) resonance the width and asy mmetry parameter of which are different with respect to that of the co re-equivalent term in the magnesium UV spectrum and (ii) a smaller wid th of the (3p4s) autoionizing line with respect to both the core hole width of the single-excitation lines and the width of the correspondin g optical term of magnesium. The position identification of the double -excitation terms, together with that of the single-excitation ones, a llows us to derive by interpolation the position of the single-ionizat ion threshold and to estimate the deviation of the inner-shell resonan ce position from the core-equivalent predictions.