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self-consistent calculation with E=0 and E=0.001a.u. (E is an external
homogeneous electric field), we can get esp_{inf} i.e. the ions do not
respond to the electric field. Now since I want to calculate esp_0 (include
the response of ions), I relax all the atoms by using 'relax'. However, I
found that all the forces on the atoms are zero even if I turn on electric
field. So how to calculate static dielectric field (esp_0) ? Why are the
forces zero even when the external electric is turned on?
      Thank you very much.

Hanghui
Department of Physics
Yale University

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Dear PWSCF users,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I am now trying to calculate the static
dielectric constant (esp_0). From the example31 in the espresso4.0
package, I know that by doing two self-consistent calculation with E=0
and E=0.001a.u. (E is an external homogeneous electric field), we can
get esp_{inf} i.e. the ions do not respond to the electric field. Now
since I want to calculate esp_0 (include the response of ions), I relax
all the atoms by using &#39;relax&#39;. However, I found that all the forces on
the atoms are zero even if I turn on electric field. So how to
calculate static dielectric field (esp_0) ? Why are the forces zero
even when the external electric is turned on?<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Thank you very much.<br>
&nbsp;<br>
Hanghui<br>
Department of Physics<br>
Yale University<br>

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