The Pre-millennium Special Theme Issue...
PiC Cover Sept-Oct 99-LR1.jpg (35635 bytes) Physics in Canada 
Vol. 55 No. 5
Sept/Oct 1999

The front cover showcases selected experiments that illustrate the infrastructure available for collaborative research in physics and chemistry in Canadian laboratories. Background: Femtosecond four and six-wave mixing laser experiments using diffractive optics at the University of Toronto (Dwayne Miller). Foreground from left to right: Apparatus used for atmospheric aerosol research at the University of Waterloo (James Sloan); Beamlines at the 1.7 MV Tandetron accelerator, University of Western Ontario, used in thin film materials research (Ian Mitchell); Multiplex coincidence spectrometer used for electron scattering studies at the University of Waterloo (Tong Leung); The Canadian Light Source to be operational in 2003 at the University of Saskatchewan (Adam Hitchcock).

 
  EDITORIAL

Chemical Physics 2000?
by K.T. Leung, University of Waterloo   pdficonsmall.gif (153 bytes)   

  FEATURE ARTICLES
1

Application of Synchrotron Light to Physics and Chemistry
by Adam P. Hitchcock, McMaster University, and John J. Neville, University of New Brunswick
Synchrotron light is an accelerator based light source that covers the complete electromagnetic spectrum from infrared to hard X-ray. It is intense, bright, fully tunable, highly polarized, and has a time structure useful for many types of dynamics experiments. Aside from the visible, near-IR and near-UV where lasers are generally superior, the properties of synchrotron light far surpass those of available lab sources. The ~ 50 facilities world wide are used by up to 20,000 scientists annually, from many disciplines, but researchers from physics and chemistry are the most prevalent. This article describes some Canadian research in this area using mainly examples from our research. It also describes the Canadian Light source, a proposed 2.9 GeV facility that will enable Canadian scientists to contribute more effectively in this arena. The future of synchrotron research in Canada is bright indeed! 

2

Femtosecond windows on physics and chemistry: Shedding new light
by Dwayne Miller, University of Toronto
This review covers recent developments in femtosecond spectroscopy with respect to the study of molecular and condensed phase phenomena. In just the last few years, a literal quantum leap in ultrafast laser technology has occurred. It is now possible to measure dynamical parameters with femtosecond (10-15 second) time resolution and deliver of peak powers in excess of 1020 W/cm2. These new capabilities make it possible to directly observe the birth of new molecules on the time scale of the "Big Bang of Chemistry", to manipulate matter with unprecedented control, and create new transiently bound states. We now have the ability to observe the fastest processes in Nature and intervene in these processes with new Light-Age tools.

3 Molecular Processes in Intense Laser Fields - from Enhanced Ionization to Coulomb Explosion Imaging
by André Bandrauk, Université de Sherbrooke
Ultrashort (t < 10 fs), intense (I ³ 1014 W/cm2) laser pulses produce highly nonlinear, nonperturbative effects in molecules such as Charge Resonance Enhanced Ionization, high order harmonic generation, with possible new applications to measuring time resolved electron-nuclear dynamics by Laser Coulomb Explosion Imaging, LCEI.
4 Probing State-to-State Molecular Dynamics
by Charles X.W. Qian, University of Victoria and Hans-Peter Loock, Queen's University
The current research in the area of state-to-state molecular photochemistry is reviewed, emphasizing particularly the research of Canadian scientists.
5 Laser Spectroscopies in the VUV and XUV
by R.H. Lipson, University of Western Ontario
A review of the techniques of VUV and XUV laser spectroscopy is presented, along with selected experimental applications from recent work being done in Canada.
6 Electron Collisions
by J.W. McConkey, University of Windsor
Whether it is in the ozone layer, the tail of a comet, a brilliant Canadian Auroral display, an X-ray interacting with the body, a plasma etching reactor in which modern high-tech electronic circuitry is birthed, or an electric discharge device used to clean up environmentally harmful waste, it is often electrons and photons which form the "soup" in which the important interactions occur. In a very real sense this is where chemistry and physics coalesce. Indeed it is precisely because electrons and photons are so critical to our understanding of so many practical, environmental and other areas, that studies of electron and photon interactions with a variety of targets at the atomic and molecular level are so necessary. In this article we look at some important aspects particularly of electron interactions.
7 Probing Technological Materials with an Electron Beam: From Bethe Surfaces and Dyson Orbitals, to co-adsorbate stabilizers and Reaction Inhibitors
by K.T. Leung, University of Waterloo
Since the discovery of the electron over a century ago, the electron beam has become an extraordinary tool for studying fundamental aspects of physics and chemistry. We present result from several experiments demonstrating the wide-ranging applications of the electron beam in chemical physics and surface science. Through momentum analysis of the scattered electrons (as in an electron energy loss experiment) or coincident detection of both the scattered and ejected electrons with preselected momenta [as in the so-called (e, 2e) method], it is possible to determine precise cross section information about the electron-induced electronic excitation and ionization processes. Such spectroscopic information of "absolute" cross sections is especially important for determining the dynamics of electron-matter collisions and the electronic structures of molecules and adsorbates, and is critically needed for modelling various industrial processes, low-temperature plasmas, atmospheric reactions, electron-surface interactions, etc. For surface processes, the use of low-energy electrons offers a powerful in-situ "non-invasive" means not only to probe, but also to activate and inhibit surface reactions. These experiments further illustrate the enormous value of electron-based fundamental research.
8 Physics and Chemistry using Fast Ion Beams
by Ian V. Mitchell, University of Western Ontario
Fast ion beams from accelerators are traditionally associated with research in nuclear physics, or at GeV particle energies, in subatomic physics.  This is to overlook the developments over the past three decades in the area of particle-solid interactions.  Detailed studies of fast particle penetration including the fundamental processes of ion energy loss and ion scattering, and of correlated collison sequences which occur for particle trajectories in single crystals, have laid the foundations for broad application of ion beam methods to materials science and engineering.  Throughout, important contributions have been made and continue to be made by Canadian laboratories.  Fast ion beam techniques now provide powerful methods for thin film and surface microanalysis, likewise they are opening unique routes to the selective modification of materials.  Applications are rich in both chemistry and physics.
9 Mobilities of Gas-Phase Ions: An Overview
by Roman Baranowski and Mark Thachuk, University of British Columbia
A brief overview of ion mobility theory and experiments is presented. Current interest in ion mobilities includes not only the testing of intermolecular potentials for atomic or small molecular ions but also includes the study of much larger ions, such as those of proteins, clusters, and organometallic compounds. A molecular dynamics method is introduced and aimed at understanding this latter class of ions. As a validation of the molecular dynamics method, mobilities, diffusion constants, ion temperatures, alignment parameters, and ion distribution functions are presented, utilizing the NO+ -He system as an example. Comparisons are made with experiment and with previous calculations.
10 Physics and Chemistry Involving Spins at Interfaces: Research In New Magnetic Materials
by David Venus, McMaster University
In the unique environment at surfaces and interfaces, atoms give expression to magnetic behaviour in novel ways. This can be exploited to gain a deeper insight into magnetism itself, and to construct artificial materials with desirable magnetic characteristics.
11 The Physics and Chemistry of Cation-Vacancy-Doped High-TC Superconductors and Other Perovskite-Based Materials
by Maureen Reedyk, Brock University
The physics and chemistry of the perovskite-based, cation-vacancy-doped systems R1-xTiO3 and Pb2Sr2R1-xCu3O8 (where R is a rare-earth) will be discussed with a focus on investigating electronic structure through measurement of the optical properties.
12 A Perspective on Molecular Electronics
by Martin Brooks, Roland Brousseau, Sylvain Charbonneau, John Cook, Yves Deslandes, Marie D’Iorio, Jane Dyment, John Luong, Paul Morley, Albert Stolow, Ye Tao, and Dan Wayner, National Research Council of Canada
Current global research on molecular electronics is reviewed, a brief forecast of further progress is made, and some current related research activity at NRC in this field is discussed. It is suggested that molecular electronics is an excellent topic for further inter-disciplinary cross-institute activity.
13 Laboratory and satellite measurements of the physics and chemistry of stratospheric clouds and aerosols
by L.E. Cymbalisty, H.E. Scott, and
James Sloan, University of Waterloo
An extensive joint effort in chemistry and physics determined the unique importance of Polar Stratospheric Clouds (PSC) to the destruction of ozone.  The heterogeneous chemistry involved depends strongly on both the phase and composition of the PSC particles, neither of which are known with any certainty.  Direct measurements of the characteristics, concentrations, and formation conditions of micron-sized particulates have been attempted by ground-based, airborne, and satellite instruments.  Comparison of field  measurements and laboratory simulations has produced some possible models for PSCs, none of which have been accepted entirely.  This paper presents a summary of the current information on PSC measurements, physicsl properties, and   heterogeneous surface chemistry. 
  PHYSICS AND EDUCATION

Canadian undergraduate programs in Chemical Physics
by Fred McCourt, University of Waterloo
 
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Acknowledgements

This project will not be possible without the support of the our sponsors: Joint Division of Surface Science, Physical and Theoretical Chemistry Division of CSC, and Photonics Research Ontario.  We are most grateful to their financial support.

 Website last updated on  August 11, 1999