
Spectroscopy and the Quantum Description of Matter FYST20, Spring Term 2011Welcome to the spring term 2011 homepage of the "Spectroscopy and the Quantum Description of Matter" course. We will start the course with a start meeting on 18th January 2011, 15.15, in H322 at the Department of Physics. The course is intended to show you how one can use spectroscopy methods to gain a quantum mechanical understanding of the properties of different forms of matter. Therefore we will study both certain aspects of the quantum mechanical description of matter as well as different spectroscopy methods. Teachers
Joachim Schnadt, joachim.schnadt@sljus.lu.se, phone: 046  2223925 ScheduleHere is a link to our schedule: FYST20schedule (updated 21 February). Form of teaching
Lectures, discussions, handin problems, lab demonstration, project works.
Lectures: The teacher will typically give a rather brief presentation and then we will discuss both in smaller groups and with the entire course. This requires that you read the material, which is handed out during the preceding lecture, prior to the meeting. ExaminationHandin problems and lab report, written report and oral presentation of the project. Marks
ECTS grading: Course materialFiles and links
Compulsory reading
Additional Reading
Exercises
Projects
Meetings and instructionsStart meeting, Tuesday, 18th January 2011Some documents from the start meeting:
Until the meeting on Thursday please read the article on XAS by G. Hähner and the excerpt on XPS from the book by Attard and Barnes (copies distributed). You also may get started with reading the compendium on the interaction of matter and light, even though we won't get started with that one before next week. If you don't understand everything and don't know all the concepts  it doesn't matter. Try instead to focus on understanding what actually is going on! Thursday, 20th January 2011First we discussed what spectroscopy is. The powerpoint presentation is found here. Then you discussed some general solid state physics and molecular physics terms using the question sheet. You probably also started discussing xray photoelectron spectroscopy (XPS) and xray absorption spectroscopy (XAS) in groups. We will finish the discussion on next Friday, 28th January. Until then, please read the first part of the compendium on the interaction of matter and light  try to get to page 25, please. On Tuesday, 25th January, Mathieu will discuss with you how to give presentations, write reports, and what projects you can do. Here is also the first handin problem. Tuesday, 25th January 2011It was discussed how to write a report and prepare and give a presentation. As an example we useed the article on the discovery of the C_{60} fullerene. Instructions for your own report and the project can be found here. The file also contains suggestions for subjects. The requirements for the report and oral presentation can be found here. Friday, 28th January 2011Cancelled due to gastric flu. Tuesday, 1st February 2011We finished the introductory discussion of XPS and XAS and started to look at the interaction of matter with light using the compendium. In particular, we had a look at the mathematical description of the photon (classically) and of a free electron (quantum mechanically). Wednesday, 2nd February 2011We continued the discussion of the interaction of matter with light, partly using the question sheet. We looked at the combined system of photon and electron/atom and then explored the implications in the electric dipole approximation. We also mentioned the magnetic dipole and electric dipole selection rules. Tuesday, 8th February 2011In the first hour we finished the discussion of the quantum mechanical description of the interaction of light and matter by looking at transitions between two discrete states and by discussing Fermi's Golden Rule. In the second hour we summarised approximations for the description of an atom and angular momentum coupling. Mathieu's presentation can be found here. Here is the second handin problem. Thursday, 10th February 2011We'll discuss the foundations for two modern methods of quantum mechanical calculations, namely the HartreeFock and Density functional theory (DFT) methods. Reading: a short excerpt from J. M. Hollas: Modern Spectroscopy, pp 199200, who nicely introduces the idea of the HartreeFock method; the section on the Hartree and HartreeFock methods in Haken & Wolf: The Physics of Atoms and Quanta, section 19.4; and the section on DFT in A. Groß: Theoretical Surface Science, section 3.3. Reading instructions can be found here. Thursday, 10th February 2011, measurement at MAXlabFor those students who participated in the experiment on Thursday Please plot the spectra below and try to assign and discuss each feature in the spectra. This means that you should explain shifts and splittings, to the extent possible. Remember that there might be a couple of different effects appearing, some of which we have discussed.
Feb2011_0126.txt Friday, 11th February 2011, measurement at MAXlabFor those students who participated in the experiment on Friday and those who could not attend the measurement Please plot the spectra below and try to assign and discuss each feature in the spectra. This means that you should explain shifts and splittings, to the extent possible. Remember that there might be a couple of different effects appearing, some of which we have discussed.
Feb2011_0302.txt Tuesday, 15th February 2011During the first hour of the course we presented typical experimental manifestations of the photoionization process. We showed how the cross section depends on the overlap between the initial an final states, what is the difference between absorption and ionization spectroscopy and describe the autoionization mechanism. The second hour was opened for questions about notation, coupling scheme and selection rules as well as discussion in groups using the question sheet about the V. Schmidt review. Powerpoint presentation from the lecture Thursday, 17th February 2011We first continued the discussion using the question sheet. A strong emphasis was put on the physics of the dipole matrix element and the consequence of the monoelectronic description within the configuration interaction framework  interferences. Then we looked at some experimental manifestations given in the V. Schmidt review: total and partial cross section, shape resonance, shakeup, shakeoff. During the last part of the course a brief recall on quantum mechanics and an introduction on attosecond spectroscopy was done. We presented how one could retrieve physical information through the phase of the dipole matrix element when the information in the energy domain is partially lost.
Question sheet from the lecture Tuesday, 22nd February 2011During the first hour, the general formalism of diatomic molecules in quantum mechanic is derived. The key point is to apply the BornOppenheimer approximation to decouple the electronic and nuclear motions. The electronic part is discussed during the rest of the course, while the nuclear part is done with a project. The second hour is dedicated to the CO project presented by Joakim. The aim of the project is to determine spectroscopic constants of different molecular states by looking at electron spectroscopy (UPS/XPS). During the project presentation the different model potentials to describe nuclear motions are introduced. Complementary information can be found in the compendium  part C. Compendium on molecules, based on a compendium by Reinhold Fink Thursday, 24th February 2011First, the symmetry properties of diatomic molecules is introduced to describe the molecular electronic wavefunction. Spectroscopic notation of electronic states and molecular orbital is presented. By inspecting the transition from separated atoms (atomic number Z1 & Z2) to unified atom (atomic number Z1+Z2), further concepts are discussed such as the dissociation of molecule, buiding up electronic configuration... The second hour is used for discussion and examples to understand electronic configuration and spectroscopic notation. The focus was set on valence and carbon1s ionization of the CO molecule. Tuesday, 1st March 2011We examine the part A of the compendium to understand:
Thursday, 3rd March 2011We introduced the Molecular Orbital diagrams with examples/exercises. We then switched to solids and summarised the basics of band structure (dispersion relation for the free electron, nearly free electron, why do gaps open in the energy bands?, ways of showing the band structure).
Material: On next Tuesday we will go on with discussing band structure and ARUPS (angleresolved ultraviolet photoemission spectroscopy, also called ARPES). Please read the following articles, with the questions on the reading instruction sheet in mind: Tuesday, 8th March 2011; Thursday, 10th MarchWe discussed why solids have band structure and why gaps open in the band structure. Further, we discussed measuring band structure using Angleresolve photoemission spectroscopy, and we converted the ARUPS data in the article by Stöhr et al. into the band structure.
Material: Tuesday, 15th March 2011We'll continue our discussion of ARUPS by looking at the band structure of graphene, using the article of T. Ohta et al.. The pdf presentation is here. In the second hour we'll have a look at the relationship of XPS and XAS and other techniques, which map the unoccupied states. Material: Article on a comparison of XAS, IPES, and twophoton photoemission.
