...structure
eg. metals, covalent bonding, etc.
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...hole
Although recent improvements have been made by Perdew et al[37].
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...CASTEP
CAmbridge Serial Total Energy Package[31]
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...CETEP
Cambridge Edinburgh Total Energy Package[31]
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...number
see Chapter 4
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...1.1eV
Also note that the highest energy valence bands are triply degenerate at the 5#5 point. It will be seen in Chapter 6 that the introduction of point defects in to the structure causes this degeneracy to be lost.
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...Lonsdalite
Hexagonal diamond.
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...sites
This small random displacement is necessary to ensure that the risk of spurious symmetries are eliminated from the relaxation procedure.
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...2.38Å
The forces are converged to better than 0.02eV/Å\ therefore the error in the bondlengths are expected to be small. This symmetry break in the new bond lengths is therefore expected to be real.
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...calculations
These calculations have been performed using the code parallelised for the CM200 Connection Machine.
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...250eV
16384 plane waves per band per k-point where used in the calculation - a total of 3276800 using 128 occupied and 72 unoccupied bands.
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...4.7533
In the reduced units given in reference [77].
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...simulation
The bonding was allowed to change when an unbonded neighbour of an atom became closer than a bonded one.
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...zero
They would be identically zero for a cubic system, but the unit cell relaxation allows this symmetry to be broken.
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...C=0
Recall from Chapter 4 that the C term in the empirical potential describes the `bond bending' interactions, which is characterised by a repulsive force between neighbouring unbonded atoms. Increasing C will increase the bulk modulus.
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...function
As found from the Fourier transform of the experimental structure factor given in reference [131].
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...case
In fact, at this compression, the system has become metallic.
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...chapter
A further silicon simulation was carried out in order to examine the fifth neighbour distances at high densities.
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Stewart Clark
Thu Oct 31 19:32:00 GMT 1996