Hello all. I have a quick question regarding the location of high symmetry points in reciprocal space and the co-ordinates you input into input.xml.

I've had a look at the Al example that comes with the exciting source code. I see that the following high symmetry points are defined in the input file:

```
<point coord=" 0.75000 0.50000 0.25000" label="W" />
<point coord=" 0.50000 0.50000 0.50000" label="L" />
<point coord=" 0.00000 0.00000 0.00000" label="GAMMA" />
<point coord=" 0.50000 0.50000 0.00000" label="X" />
<point coord=" 0.75000 0.50000 0.25000" label="W" />
<point coord=" 0.75000 0.37500 0.37500" label="K" />
```

but I cannot seem to tally these co-ordinates with those in the Brillouin zone. The gamma point is at the centre of the zone and is being taken as the origin, but I'm having difficulty in figuring out why the other points have their specified locations. As I understand it, the gamma, K, x and w points are all co-planar, but each have different values of 'z'. I also understand that the x point is taken to be at the centre of a square face in the Brillouin zone and along the y-direction but that doesn't seem to be the case here.

I have tried to determine the band structure of my material (MnSb) which is a hexagonal crystal but the points that I have used do not seem to be high symmetry points and, frankly, the plotted band structure is a mess! The following are the co-ordinates that I use:

```
<point coord="0.00000 0.00000 0.00000" label="GAMMA" ></point>
<point coord="0.75000 0.43300 0.00000" label="M" ></point>
<point coord="1.00000 0.00000 0.00000" label="K"></point>
<point coord="0.00000 0.00000 0.00000" label="GAMMA" ></point>
<point coord="0.00000 0.00000 1.00000" label="A" ></point>
<point coord="0.75000 0.43330 1.00000" label="L" ></point>
<point coord="1.00000 0.00000 1.00000" label="H" ></point>
```

I calculated these co-ordinates with James Annett during last year's Psi-k DFT workshop held at Bristol University. We were happy that, given the definition of the gamma point being the origin and the location of the high symmetry points given at http://www.ioffe.ru/SVA/NSM/Semicond/Append/figs/fmd21_5.gif that these co-ordinates were correct, but that does not seem to be the case.

So, my questions are: how were the aluminium high symmetry points determined and what are the corresponding points for the hexagonal Brillouin zone?

Kind regards,

James