* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download King Abdulaziz University, Department of Physics, Jeddah
X-ray fluorescence wikipedia , lookup
Bremsstrahlung wikipedia , lookup
Density functional theory wikipedia , lookup
Molecular Hamiltonian wikipedia , lookup
Canonical quantization wikipedia , lookup
Hydrogen atom wikipedia , lookup
Elementary particle wikipedia , lookup
History of quantum field theory wikipedia , lookup
Chemical bond wikipedia , lookup
Quantum electrodynamics wikipedia , lookup
Ferromagnetism wikipedia , lookup
Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup
Tight binding wikipedia , lookup
X-ray photoelectron spectroscopy wikipedia , lookup
Auger electron spectroscopy wikipedia , lookup
Wave–particle duality wikipedia , lookup
Atomic orbital wikipedia , lookup
Atomic theory wikipedia , lookup
King Abdulaziz University, Department of Physics, Jeddah HOMEWORK ASSIGNMENT #7, PHYSICS 471, SPRING, 2013 Deadline: 9 AM, Saturday, (Jumaada II 24, 1434) May 4, 2013 Name:…………………………………..……... ID:……………….. Signature:……………….. 1- What are achievements of the quantum Fermi gas model? - Successful prediction of basic thermal properties of metals Successful prediction of conductivity 2- What are failures of the quantum Fermi gas model? - Failure to predict a positive Hall coefficient No understanding whatever of insulators 3- What is the major assumption of classical free electron model (Drude)? Metal is an array of positive ions with electrons that are free to roam through the ionic array. 4- What is the major assumption of quqntum mechanical free electron model (Sommerfeld)? Electrons are in a potential well with infinite barriers: They do not leave metal, but free to roam inside. 5- Regarding electrons, what is the assumption of classical free electron model (Drude)? Electrons are treated as an ideal neutral gas, and their total energy depends on the temperature and applied field. 6- Regarding electrons, what is the major assumption of quqntum mechanical free electron model (Sommerfeld)? Electron energy levels are quantized and well defined, so average energy of electron is not equal to (3/2)kBT. 7- In classical model, in the absence of an electrical field, what will happen to the electrons? In the absence of an electrical field, electrons move with randomly distributed thermal velocities. 8- In quantum mechanical model, according to what electrons occupy energy? Electrons occupy energy levels according to Pauli’s exclusion principle. 9- In brief, write the limitations of the FEG model of Drude? - The positive ions act only as scattering centers and is assumed to have no effect on the motion of electrons between collisions Interactions between electrons are ignored 10- Describe the movement of electrons in the two models (Drude & Sommerfeld)? - For Drude: Large number of particles moving slowly. For Sommerfeld: Small effective number of particles moving very fast, due to special quantum mechanical constraints