An yttrium Mξ source for ESCA

A new source for producing YMξ radiation in an ESCA spectrometer is described. The system makes use of continuous evaporation of yttrium on a rotating anode. It is demonstrated that this scheme allows YMξ-excited electron spectra to be recorded without gradual loss of resolution and intensity due to anode oxidation. Electron spectra of Ar, Hg and N₂ excited by YMξ radiation are studied. Relative photoelectric cross-sections of the 5d_{$\text{5}\text{2}$}, 5d_{$\text{5}\text{2}$} and 6s orbitals in Hg and the four valence orbitals in N₂ are measured. The valence electron shake-up spectrum of N₂ is discussed.     

Fluorine Kα radiation for the excitation of electron spectra

The applicability of the F Kα X-ray line (hv = 676 eV) from potassium fluoride for the excitation of electron spectra is demonstrated. Relative photoionization cross-sections in Au and gaseous Hg have been measured. The F Kα radiation from KF, RbF and CsF has been studied. The Ba Mζ line (hv = 602 eV) is found to be too broad for use in ESCA, even when emitted from metallic barium.     

A direct approach to Bergman kernel asymptotics for positive line bundles

We give an elementary proof of the existence of an asymptotic expansion in powers of k of the Bergman kernel associated to L ^k , where L is a positive line bundle over a compact complex manifold. We also give an algorithm for computing the coefficients in the expansion.     

A Sobolev mapping property of the Bergman kernel

We prove that if D is a pseudoconvex domain with Lipschitz boundary having an exhaustion function such that is plurisubharmonic, then the Bergman projection maps the Sobolev space boundedly to itself for any . Received March 10, 1999 / Published online May 8, 2000     

Calibration of electron spectra

Energy calibration procedures, which have been used in ESCA, are reviewed. Binding energies of calibration lines suitable for solid and for gaseous samples have been determined. Charging effects of nonconducting samples have been investigated for different X-radiation, sample thickness and material. A calibration relative to lines from some insulating standard compound mixed into the sample was shown to be unreliable, while experiments indicated that in calibrating relative to a surface layer, the carbon line from the hydrocarbon contamination layer can be used as well as a line from a thick layer of a noble metal on a part of the sample.