# Difference between revisions of "Tutorial:Kronig-Penney Model"

In this tutorial we calculate the bandstructure for Kronig-Penney Model. The Kronig-Penney Model is a simplified 1D electron in a lattice, where the lattice is a series of potential barriers.

## Input

The following input file will be used for the ground state calculation:

````CalculationMode` = gs
`ExtraStates` = 4
`PeriodicDimensions` = 1
`Dimensions` = 1
`TheoryLevel` = independent_particles

a = 5
b = 1
V = 3

`Lsize` = (a + b)/2

`Spacing` = .005

%`Species`
"B" | species_user_defined | potential_formula | "(x>-b)*V*(x<0)" | valence | 1
%

%`Coordinates`
"B" | 0 |
%

%`KPointsGrid`
11 |
%

%`KPointsPath`
11 |
0.0 |
0.5 |
%

`ConvEigenError` = true
```

## Bandstructure

To calculate the bandstructure simply change the input file to the following:

````CalculationMode` = unocc
`ExtraStates` = 4
`PeriodicDimensions` = 1
`Dimensions` = 1
`TheoryLevel` = independent_particles
```
```a = 5
b = 1
V = 3
```
````Lsize` = (a + b)/2
```
````Spacing` = .005
```
```%`Species`
"B" | species_user_defined | potential_formula | "(x>-b)*V*(x<0)" | valence | 1
%
```
```%`Coordinates`
"B" | 0 |
%
```
```%`KPointsGrid`
11 |
%
```
```%`KPointsPath`
11 |
0.0 |
0.5 |
%
```
````ConvEigenError` = true
```