A system for the acquisition of angle-resolved photoelectron spectra is described. The sample gas is excited by VUV resonance radiation, which is polarized to about 95% using a fully rotatable fourfold reflection polarizer. One of the mirrors is toroidally shaped in order to focus the radiation into the sample gas cell. This design gives count rates comparable to those obtained by an unpolarized source, and at a greatly reduced background level. A computer controlled system has been developed to automate the recording procedure. It allows for simultaneous recordings of the spectra at the different angular settings, thus eliminating the effects of intensity drifts. Details of calibration procedures and data processing, including spectrum analysis, are given along with a discussion of the accuracy of the results. To illustrate the performance, measured β-values for the main components of the four outermost photoelectron bands in the Hel excited spectrum of CO2 are presented.

Using a DC discharge VUV source equipped with a rotating, focusing reflection polariser in conjunction with a hemispherical electron spectrometer, the angular distribution of photoelectrons from the outermost p levels in the noble gases Ar, Kr and Xe was measured in the kinetic-energy region 0-3 eV. Discharges in Ne, Ar, Kr, Xe and N2 are used to obtain photons with energies in the range 11-19 eV. For photon energies between the ionisation thresholds for the P3/2 and P1/2 levels, observed rapid oscillations in beta are correlated with resonances with autoionising states. For higher photon energies, the energy dependence of beta is smooth.

The He(I) excited and angle-resolved photoelectron spectrum of CO2 is investigated using a focussing VUV-polarizer. High resolution combined with the additional information given by comparing spectra taken at different angles permits detailed analysis of the vibrational structure. β-values are given for all vibrational components hitherto observed in the photoelectron spectrum of the ≈X, ≈A,≈B and ≈C electronic bands. Single excitations of the v3 mode with vibrational energies 181 meV in the estate and 279 meV in the ≈B-state are reported. The peak at 360 meV vibrational energy in the (≈C-state is reinterpreted as a single v3 excitation. The β-values of the most intense peaks are also measured using Ne(I) (16.67 and 16.85 eV), Ne(II) (26.86 and 26.95 eV) and He(II) (40.81) resonance radiations.

The photoelectron spectrum of CO2 excited by polarised He I radiation is investigated in the binding energy region 18.0-18.7 eV, using a focusing VUV polariser at an energy resolution of 15 meV (FWHM). Comparison of spectra taken at different polariser settings makes it possible to give vibrational assignments and beta values for 18 bands belonging to the B2 Sigma u+ state and 6 bands from the A2 Pi u state. The v3 energy in the B state is 230 meV.

A new electron spectrometer for kinetic energies below 100 eV is presented. It uses the time-of-flight technique and combines high resolution with high luminosity. A permanent magnet with soft iron pole pieces generates a rotationally symmetric magnetic field with 1r2 dependence. This field makes it possible to confine very long real flight paths within small physical dimensions. The analyzer has an overall diameter of about 0.3 m and the use of an iron magnet makes it practically insensitive to external magnetic fields. Electronic equipment for pulsing and detection is described. A transmission measurement of the 1s2s2 resonance in He− is used to test the performance of the spectrometer.

A high duty cycle multichannel analyzer has been designed and used in time-of-flight electron spectroscopy. The memory capacity is 64K counts. The number of channels is 8192 with a time resolution of 100 ns. An oscilloscope is used to display the spectra synchronous with the counting. The unit has been built with standard electronic components.

The outer valence region in CS2 has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X $̃2Πg, A $̃2Πu, B $̃2Σ+u and C $̃2Σ+g bands. Some of the fine-structure peaks in the X ,̃ B $̃and C $̃bands are shown to be pressure-dependent. The reason for the pressure dependence is assumed to be inelastic scattering of electrons emitted in the adiabatic transitions. It is established that the two CI satellite bands present in the He(I)-excited spectrum contain vibrational structure.