A variable angle photoelectron spectrometer using a position-sensitive detector

The creation and subsequent Auger decay of the 3d −1 core-hole state in HBr is studied using two-dimensional photoelectron spectroscopy. In this technique the yield of electrons is collected as a function of both photon and electron kinetic energy. The effects of post-collision interaction (PCI) observed in the energy shift of the HBr + (3d −1 ) photoelectron lines. The energy shifts are compared with previous experimental results on Kr. This comparison suggests that the molecular nature of HBr has little effect on the PCI energy exchange mechanism.

Section: Methodsmentioning

confidence: 99%

Observation of post-collision interaction (PCI) in HBr using two-dimensional photoelectron spectroscopy

Odling-Smee

Sokell

Wills

et al. 1999

“…These measurements were performed at the Daresbury Synchrotron Radiation Source on the McPherson 5m normal incidence monochromator. The experimental arrangement has been described previously (Haworth et al 1985(Haworth et al , Čubrić et al 1992. In outline, a monochromated photon beam was crossed with gaseous N 2 O molecules effusing from a hypodermic needle.…”

Section: Methodsmentioning

confidence: 99%

A two-dimensional study of the autoionizing decay routes of Rydberg states converging on the ionization threshold in

Sokell

Wills

Comer

et al. 1997

The autoionizing decay pathways of the five-dipole allowed Rydberg series converging on the C 2 + threshold in N 2 O have been investigated using two-dimensional photoelectron spectroscopy. Measurements of electron yield as a function of both electron and photon energy have been carried out using tuneable synchrotron radiation. The vast majority of vibrational levels of the three bound electronic states of the ion that are accessible to the decaying Rydberg states have been studied with an experimental resolution of approximately 30 meV. This was sufficient to study transitions to individual vibrational levels. The comprehensive nature of the data presented has enabled various observations pertaining to both electronic and vibrational selectivity in the autoionizing decay processes to be made.The observed preference for the decay of npσ and npπ Rydberg states to the X 2 and A 2 + states of the ion respectively may be explained if the emitted electron conserves its angular momentum. Members of the ndπ series result in the most intense features in the spectrum of the only available ion state (B 2 ) that has a nuclear arrangement which is significantly different from that of the autoionizing states. It appears that dissociative, neutral states are more likely to be accessed from ndπ states and it seems plausible that these dissociative states play a role in the resonant population of the B 2 state. There is also evidence to suggest that this B 2 state has a bent equilibrium geometry.

“…Comer and co-workers (Haworth et al 1985) have developed a photoelectron spectrometer for CIS measurements that employs a position-sensitive detector. The power of the apparatus is that a range of kinetic energies can be measured simultaneously.…”

Section: Constant Ion State Spectroscopymentioning

confidence: 99%

“…Thus an experimental procedure where the incident photon energy and the kinetic energy of the photoelectron are ramped synchronously is no longer a suitable method to measure the partial cross section. Only the two-dimensional surfaces obtained with the method introduced by Haworth et al (1985) can give the complete picture of the process and a correct measurement of the partial cross section.…”

Section: The Other Rare Gases and Inner-shell Doubly Excited Statesmentioning

confidence: 99%

Double-excitation and double-escape processes studied by photoelectron spectroscopy near threshold

King

Avaldi

2000

Recent experimental work using photons to study double excitation, double escape and related processes near their respective thresholds is reviewed. These processes are of significant current interest because they are completely determined by electron-electron correlations. In particular, experimental studies based on the techniques of low-energy electron spectroscopy are described. By using selected examples from coincidence and non-coincidence experiments the various kinds of dynamic and spectroscopic information that can be obtained are illustrated. Recent results, mainly in the rare gases, are described and their interpretation is discussed. Future perspectives are considered. ContentsContents 215 1. Introduction 216 2. The detection of zero-energy (threshold) photoelectrons 220 2.1. Introduction 220 2.2. Threshold photoelectron spectroscopy and the penetrating field technique 220 2.3. Threshold photoelectron coincidence spectroscopies: TPEsCO, TPEPECO and TPEPICO techniques 223 2.4. (γ , 2e) coincidence techniques 224 2.5. The COLTRIMS technique 229 2.6. Constant ion state spectroscopy 231 3. Near-threshold photodouble ionization: studies involving the detection of a single electron 233 3.1. Introduction 233 3.2. The Wannier picture of threshold photodouble ionization 234 3.3. The shape of the double-ionization cross section in helium close to threshold 235 3.4. Angular behaviour of the photoelectrons in near-threshold photoionization of helium 240 3.5. The other rare gases 243 4. Near-threshold photodouble ionization: electron-electron coincidence studies 245 4.1. Introduction 245 4.2. Threshold photoelectrons coincidence studies of the rare gases 246