scholarly journals Photoionization Dynamics of Small Molecules With Synchrotron Radiation: State Preparation by Pepico and Tpepico

1991 ◽  
Vol 11 (3-4) ◽  
pp. 131-142 ◽  
Author(s):  
Paul Marie Guyon
Keyword(s):  
Synchrotron Radiation ◽  
Small Molecules ◽  
Internal Energy ◽  
Photoelectron Spectroscopy ◽  
Time Of Flight ◽  
Initial State ◽  
Final State ◽  
State Preparation ◽  
Synchroton Radiation

The use of synchroton radiation combined with TPEPICO experiments to study the photoionization dynamics of molecules at Orsay's synchroton radiation facility is discussed. The initial state preparation by Threshold Photoelectron Spectroscopy and final state-mass and internal energy spectroscopy by time of flight analysis of photoelectrons as well as ions in coincidence with threshold electrons is illustrated by the TPES of HCl, the TOF TPES of O2 and the TPEPICO spectra of NO+ fragments from the decay of state selected N2O+ ions.

scholarly journals Observation of Ionization of Laser Excited Atoms by Synchrotron Radiation

1984 ◽  
Vol 86 ◽  
pp. 128-131
Author(s):  
J.M. Bizau ◽  
F. Wuilleumier ◽  
P. Gerard ◽  
P. Dhez ◽  
B. Carré ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Oscillator Strengths ◽  
Final States ◽  
Initial State ◽  
Final State ◽  
Core Electron ◽  
Output Mirror ◽  
Initial States ◽  
A New Technique

We have begun a program to measure oscillator strengths of autoionizing resonances that result from a transition in the VUV between a laser excited initial state and a final state in which a core electron is promoted. These measurements demonstrate a new technique to combine synchrotron radiation, laser pumping, and photoelectron spectroscopy.Measurements of the energy positions of autoionizing resonances have been honed to a fine art over the past 50 years. Total cross section measurements and the parameters that describe autoionizing resonances have been determined. Most of these studies have been made from the dipole allowed ground state. Recently autoionizing resonances have been observed from excited initial states and from ion initial states. We have heard several talks, at this meeting which described some of this type of research. In the measurements to be described in this paper, laser radiation is combined with synchrotron radiation, as shown schematicaly in Figure 1, to study the photoionization from excited initial states to continuum final states or to autoionizing final states. Continuum radiation from the Aneau de Collisions d’Orsay (ACO), which is installed at the Universite de Paris-Sud, in Orsay France, is monochromatized by a toroidal grating monochromator (TGM) and is focused by a toroidal output mirror on to a weakly collimated sodium beam emanating from a furnace mounted on the axis of a cylinderical mirror analyzer (CMA). This electron spectrometer is used to study the kinetic energy distribution of the ejected photoelectrons produced by the interaction of the photon beam with the focused synchrotron radiation.

scholarly journals Time‐of‐flight photoelectron spectroscopy of gases using synchrotron radiation

1979 ◽  
Vol 50 (10) ◽  
pp. 1268-1273 ◽  
Author(s):  
M. G. White ◽  
R. A. Rosenberg ◽  
G. Gabor ◽  
E. D. Poliakoff ◽  
G. Thornton ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Time Of Flight

Chemical Thermodynamics

2009 ◽  
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Internal Energy ◽  
Thermodynamic Quantity ◽  
Energy Change ◽  
Chemical Thermodynamics ◽  
State Function ◽  
Initial State ◽  
Final State ◽  
Spontaneous Process ◽  
The Law ◽  
The Universe

Chemical thermodynamics is the study of the energy changes and transfers associated with chemical and physical transformations. Energy is the ability to do work or to transfer heat. A spontaneous process is one that can occur on its own without any external influence. A spontaneous process always moves a system in the direction of equilibrium. When a process or reaction cannot occur under the prescribed conditions, it is nonspontaneous. The reverse of a spontaneous process or reaction is always nonspontaneous. Heat (q) is the energy transferred between a system and its surroundings due to a temperature difference. Work (w) is the energy change when a force (F) moves an object through a distance (d). Thus. . . W = F ×d. . . . A system is a specified part of the universe (e.g., a sample or a reaction mixture we are studying). Everything outside the system is referred to as the surroundings. The universe is the system plus the surroundings. A state function is a thermodynamic quantity that defines the present state or condition of the system. Changes in state function quantities are independent of the path (or process) used to arrive at the final state from the initial state. Examples of state functions include enthalpy change (ΔH), entropy change, (ΔS) and free energy change, (ΔG). The internal energy of a system is the sum of the kinetic and potential energies of the particles making up the system. While it is not possible to determine the absolute internal energy of a system, we can easily measure changes in internal energy (which correspond to energy given off or absorbed by the system). The change in internal energy, . . . ΔE, is: ΔE = Efinal –Einitial. . . . The first law of thermodynamics, also called the law of conservation of energy, states that the total amount of energy in the universe is constant, that is, energy can neither be created nor destroyed. It can only be converted from one form into another. In mathematical terms, the law states that the change in internal energy of a system, ΔE, equals q+w. That is,. . . ΔE = q+w. . . In other words, the change in E is equal to the heat absorbed (or emitted) by the system, plus work done on (or by) the system.

π* ← π Shakeup Satellites for the Analysis of Structure and Bonding in Aromatic Polymers by X-Ray Photoelectron Spectroscopy

1986 ◽  
Vol 40 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Joseph A. Gardella ◽  
Susan A. Ferguson ◽  
Roland L. Chin
Keyword(s):  
Quantitative Analysis ◽  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Polymer Surface ◽  
Surface Region ◽  
Initial State ◽  
Final State ◽  
Near Surface ◽  
Peak Fitting ◽  
Pi Orbitals

The applications of ESCA to polymer surface analysis include the use of the secondary final-state effects which lead to satellite structure near the core-level photoemission (PE) lines. Specifically, unsaturated and aromatic functionalities in organic compounds and polymers lead to π* ← π shakeup peaks of less than 10 eV lower kinetic energy (higher binding energy). In the surface analysis of polymers, these features can be utilized for qualitative analysis, identification of the presence and structure of aromatic bonding, and quantitative analysis in determining the amount of a particular block or the aromatic containing function in the near-surface region. Carbon Is shakeups are most often used, but the present study includes detailed qualitative and quantitative analysis of shakeup structures from PE lines from each type of atom in hydrocarbon-, siloxane-, and sulfur-containing polymers. These results show the importance of including the shakeup intensity in quantitative peak area calculations and in peak fitting of complex PE envelopes. These studies prove in a variety of systems that the effects of third-row atoms on the final state lead to the presence of shakeup features in atoms with orbitals which do not participate in the aromatic orbital initial state, thus complicating interpretation of structure from the presence of these features. Results from the siloxane and sulfone polymers indicate that previously held assumptions about the nature of the initial-state molecular orbital may overlook the contribution of empty 3d orbitals or increased charge density on the Si or S atom which would spread the pi orbitals to the oxygen in the aromatic siloxane or sulfone systems. Finally, analysis of these features can provide quantitative analysis of polymeric surface structure by monitoring the relative intensity of the feature to the main PE line.

Time of flight photoelectron spectroscopy using synchrotron radiation study of resonances in O2

1980 ◽  
Vol 77 ◽  
pp. 605-612 ◽  
Author(s):  
P. Morin ◽  
I. Nenner ◽  
P.M. Guyon ◽  
O. Dutuit ◽  
K. Ito
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Time Of Flight ◽  
Radiation Study

scholarly journals Attosecond intra-valence band dynamics and resonant-photoemission delays in W(110)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. Heinrich ◽  
T. Saule ◽  
M. Högner ◽  
Y. Cui ◽  
V. S. Yakovlev ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Electronic Band Structure ◽  
Photoelectric Effect ◽  
Final State ◽  
Electronic Band ◽  
Time Resolved ◽  
Resonant Photoemission ◽  
Pulse Trains ◽  
Electron Correlation Effects

AbstractTime-resolved photoelectron spectroscopy with attosecond precision provides new insights into the photoelectric effect and gives information about the timing of photoemission from different electronic states within the electronic band structure of solids. Electron transport, scattering phenomena and electron-electron correlation effects can be observed on attosecond time scales by timing photoemission from valence band states against that from core states. However, accessing intraband effects was so far particularly challenging due to the simultaneous requirements on energy, momentum and time resolution. Here we report on an experiment utilizing intracavity generated attosecond pulse trains to meet these demands at high flux and high photon energies to measure intraband delays between sp- and d-band states in the valence band photoemission from tungsten and investigate final-state effects in resonant photoemission.

Sign in / Sign up

Export Citation Format

Share Document