# Calculation of InAS WurtZite bragg peak position

1. Sep 6, 2012

### poul

Hey

If I have a InAs Wurtzite structure, and now the a and c parameter from tables. How can i calculate the distance between (1 0 3/2)_sur layers? (in surface coordinates)

I need it to find the angle of reflection, for a (1 0 3/2) WZ InAs peak.

Is it just so simple?

(1 0 3/2)_sur = (7/6 7/6 -5/6)_cubic (in cubic coordinates)
And then the distance is just
d=2*pi/G_hkl= a_cub / (sqrt(123/36))

And then i can just use braggs law
2dsin(angle)=wavelength

2. Sep 6, 2012

### strangedude

Not a 100% sure what you are asking, but as I understand it you want to find the 2θ angle of your peak in a diffractogram?

If so the calculation should be straight forward. I.e. use whatever miller indice you want, find the corresponding d- value (i.e. plane spacing) for your specific lattice and then use Bragg's law.

Keep in mind that the Wurtzite structure is hcp and the commutative restraints that puts on Miller indices.

Or you could just download PowderCell, enter the structure data, and let it calculate it for you!

If I misunderstood you, please let me know and I'll see if I can help.
Hope this is of use!

Last edited: Sep 6, 2012
3. Sep 7, 2012

### M Quack

If you only want the scattering angle, then yes, it is that easy.

Otherwise you have to figure out the exact relation between the standard and surface reciprocal space bases.

How to calculate diffractometer angles from that is very nicely described by Busing and Levy (1967).

http://scripts.iucr.org/cgi-bin/paper?a05492