# Tag Info

5

Metals are good conductors of electricity because the outer (valence) electrons of the metal atoms are only loosely bound to the nucleus and form molecular orbitals known as the conduction band. Electrons can move more or less freely through the conduction band and so metals conduct electricity generally well. When a metal is chemically oxidised its outer ...

2

Since the question is rather vague, I will just give you some key points: Debye's model treats oscillation modes of a solid as sound waves (phonons) with frequency $\omega(\mathbf{k})=v|\mathbf{k}|$ ($v$ the sound velocity). As a result, with this model, Debye shows how the heat capacity is directly related to the rate of change of the energy expectation ...

2

Magnetic fields certainly can influence thermal conductivity. This shows up, not surprisingly, when there is a strong influence of the magnetic field on other properties, particularly electronic ones. One (non-metal) example is 'Thermal conductivity tensor in YBa$_{2}$Cu$_{3}$O$_{7-x}$: Effects of a planar magnetic field' by R. Ocana and P. Esquinazi, Phys ...

2

After x-rays hit a substance they will be scattered in all directions; if the material is a crystal then you will obtain a diffraction pattern where each point is created by the constructive interference of the scattered rays. The connection between the diffraction pattern and the reciprocal space is readily found: take a crystal and consider an atom ...

1

I would say the maths and equations are pretty much identical except in H NMR you would use the gyromagnetic ratio for a proton, while in EPR you use the data for an electron. Both are spin 1/2 systems. In terms of medical imaging it is easier to pick H2O via pulse NMR (rather than continuous field i.e what chemists do for molecules etc) than observe free ...

1

I don't believe that the thermal conductivity of most metals is very sensitive to magnetic fields. Yes, there will be some field-induced band shifting in the case of an itinerant ferromagnet which, in principle, leads to a change in the density of states at the Fermi level, but that will typically be a very small effect. If the magnetic field induced ...

1

These lectures on the QHE and FQHE given at the Les Houches summer school are a great start imho.

1

Caesium From: "Physics 1942 – 1962: Including Presentation Speeches and Laureates' Biographies" by Yong Zhou

1

Density Functional Theory (DFT) is used to calculate the electronic structure and properties of metals as much and "successfully" as it is used for molecules, clusters, alloys, insulators and semiconductors. Of course there are certain things that DFT is good at and can and cannot do. However saying that "DFT calculations are not accurate for metallic ...

1

When a liquid or solid evaporates, it turns into a gas. In a closed container, pressure builds as gas accumulates. There are two competing processes. In the solid or liquid, the higher energy atoms at the surface fly off. In the gas, the slower atoms stick to the surface and condense. The number of atoms available to condense is proportional to the gas ...

1

I think they are probably trying to characterize small mechanical devices. One part of this analysis would be analyzing their motion. One motion it can do is to vibrate. If the wavelength of the vibration is much smaller than the size of the object, then the vibration can't tell how small the object is, and the vibration will behave the same way it would ...

1

I think what they are trying to say is that in a lattice of ions, the waves propagate at the plasma frequency only if we can assume that the interaction between ions is sufficiently small (this assumption is contained in the part "is only valid if the forces between ions separated by R are negligibly small for R of order 1/k"). But in a bare lattice of ...

1

Yes, the restoring force will be equal to the deforming force once equilibrium is reached. But before that, the deforming force will be greater than the restoring force, and deformation will occur then. Once equilibrium is reached, no more deformation occurs.

Only top voted, non community-wiki answers of a minimum length are eligible