exercises:2016_uzh_cmest:calculating_pdos
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
exercises:2016_uzh_cmest:calculating_pdos [2016/10/30 16:33] – tmueller | exercises:2016_uzh_cmest:calculating_pdos [2020/08/21 10:15] (current) – external edit 127.0.0.1 | ||
---|---|---|---|
Line 6: | Line 6: | ||
* hexagonal Boron Nitride | * hexagonal Boron Nitride | ||
- | Both feature the same 2D crystal structure with the only difference being the lattice constant and that one consists of only carbons and the other of boron and nitride. | + | Both feature the same 2D crystal structure with the only difference being the lattice constant and that one consists of only carbons and the other of boron and nitrogen. |
Similar to the previous exercise we write the coordinates in term of the unit cell: | Similar to the previous exercise we write the coordinates in term of the unit cell: | ||
Line 57: | Line 57: | ||
# print all projected DOS available: | # print all projected DOS available: | ||
NLUMO -1 | NLUMO -1 | ||
+ | # split the density by quantum number: | ||
COMPONENTS | COMPONENTS | ||
&END | &END | ||
Line 69: | Line 70: | ||
SYMMETRY HEXAGONAL | SYMMETRY HEXAGONAL | ||
PERIODIC XYZ | PERIODIC XYZ | ||
- | # and replicate | + | # and replicate |
- | MULTIPLE_UNIT_CELL 2 2 2 | + | MULTIPLE_UNIT_CELL 2 2 1 |
&END CELL | &END CELL | ||
+ | & | ||
+ | # also replicate the topology (see text): | ||
+ | MULTIPLE_UNIT_CELL 2 2 1 | ||
+ | &END TOPOLOGY | ||
&COORD | &COORD | ||
SCALED | SCALED | ||
Line 79: | Line 84: | ||
&KIND C | &KIND C | ||
ELEMENT C | ELEMENT C | ||
- | BASIS_SET | + | BASIS_SET |
POTENTIAL GTH-PBE | POTENTIAL GTH-PBE | ||
&END KIND | &END KIND | ||
Line 87: | Line 92: | ||
</ | </ | ||
- | The replication of the unit cell before doing the calculation | + | The replication of the unit cell is necessary since the program samples |
+ | |||
+ | What you will get in addition to the output file is a file named '' | ||
+ | |||
+ | < | ||
+ | | ||
+ | # MO Eigenvalue [a.u.] | ||
+ | d0 | ||
+ | | ||
+ | | ||
+ | [...] | ||
+ | </ | ||
+ | |||
+ | The columns correspond to the orbitals present in the basis set (hence // | ||
+ | |||
+ | Please also note the unit of the energy, it is in $E_h$. When looking at DOS plots you may want to convert it to Electronvolt instead. | ||
+ | |||
+ | While some of the new options to help with convergence are of numerical nature, [[howto: | ||
+ | |||
+ | * Repeat the above calculation for the different multiple cells 3x3x1, 4x4x1, 5x5x1, 6x6x1 and 7x7x1 | ||
+ | * Even though you are not required to do any smoothing, create the DOS plots for each simulation. | ||
+ | * Do you see why it is necessary to do the unit cell replication? | ||
+ | * .. which state ($s$, $p_x$, ..) is mainly responsible for that? | ||
+ | * Repeat the calculations for h-BN instead (use the DZVP-MOLOPT-SR-GTH basis set for boron instead of the DZVP-MOLOPT-GTH and change the lattice constant to $2.504 Å$). | ||
+ | * Create the plots again (remember: now there are two pdos files, one for each kind). What is the clear difference to graphene? | ||
+ | * Do you now understand why we need smearing? |
exercises/2016_uzh_cmest/calculating_pdos.1477845234.txt.gz · Last modified: 2020/08/21 10:15 (external edit)