# [Pw_forum] Using mixture of pseudo potential

Vi Vo vovi47 at yahoo.com
Tue May 31 19:11:48 CEST 2011

```Hi Pine,

Thank you.  Yes, I know that I have to do different tests for ecutrho and
ecutwfc, but my questions are different. I would like to know what is the
default setting for ecutrho the code would assume. I restate my question as
follows:

If I forgot to specify the ecutrho, what default value of  ecutrho would the
code assume for US PP?  (I guess it still uses the default ecutrho=4*ecutwfc).

On the other hand, assuming I set the ecutrho=9*ecutwfc, does then the same
value of ecutrho=8*ecutwfc also apply to NC PP, or does the value of
ecutrho=4*ecutwfc will be used for NC PP.

Thank you,

Vi

________________________________
From: lucking-pine <songsong19840614 at gmail.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Mon, May 30, 2011 9:35:59 PM
Subject: Re: [Pw_forum] Using mixture of pseudo potential

Hi,
In my way,I usually test ecutrho = X*ecutwfc using scf or relax.I look the
result of total energy or enthalpy.
Such as:
1.ecutwfc=47 ecutrho=400, total energy= -290.983
2.ecutwfc=47 ecutrho=380, total energy= -290.993
So,I thought '2' is better than '1'.

Bests,
Pine.

2011/5/31 Vi Vo <vovi47 at yahoo.com>

Dear All,
>
>In my calculation, I used a mixture of pseudo potentials, ie. norm-conserving pp
>(NC pp)  for one element and ultrasoft pp (US pp) for another.  If I don't
>specify ecutrho in the input, what will be the default value for ecutrho for the
>ultrasoft pp.  I know that for NC pp, ecutrho = 4*ecutwfc, but I do not know if
>the same value is used for US pp.  On the other hand, if I specify ecutrho =
>8*ecutwfc, then does the same value apply to the NC pp.
>
>Thank you very much,
>
>Vi
>University of Houston
>
>
>
>_______________________________________________
>Pw_forum mailing list
>Pw_forum at pwscf.org
>http://www.democritos.it/mailman/listinfo/pw_forum
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20110531/1bc2fffd/attachment.html>
```