Re: [D3q-discuss] question about group velocity unit

[david y. <dya...@gm...>]

Thanks so much. This is very helpful

One unrelated query (just out of curiosity): I see that we can convert IFCs
from the Finite difference method (from ShengBTE) into thermal2.  Is there
a  way to achieve opposite: Using D3Q IFCs into ShengBTe?

Thanks

Regards
David

On Tue, Jun 23, 2020 at 2:30 PM Lorenzo Paulatto <pa...@gm...> wrote:

> Hello David, unfortunately the unit of velocity is a bit of a mess. If
> you are reading it from a file produced by d3_tk.x using the option
> store_lw=.true. then the unit is actually Ry. But if you get it from
> d3_r2q.x then there is a RY_TO_CMM1 factor in it, which mean that you
> have to divide by ( 13.6058 * 8065.5 ). I'm going to ix this sooner or
> later... If you want to get rid of this factor you can just remove it
> from line 773 of of PROGRAM_r2q.f90 and recompile
>
> regards
>
> On 6/23/20 11:34 AM, david yang wrote:
> > Dr. Paulatto,
> >
> > I  have some doubt about the unit of group velocity in thermal code. The
> > manal says they in Rydberg (Rydberg bohr ? ) unit with the conversion of
> > (1.09*10^6) m/sec
> >
> > If I use this My velocity comes out 407.581209999999998672*1.09*10^6,
> > which is too large to be correct.
> >
> > Simply by taking the slope of the dispersion I get about ~3400 m/sec
> > which is in the right ballpark.
> >
> > I would appreciate if you could point out my error here.
> >
> > Thank you
> > David
> >
> >
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>
> --
> Lorenzo Paulatto - Paris
>