<p>Dear all,</p>
<p>I have a question regarding the units of "finite electric fields" reported in the input webpage of the PW.x code:</p>
<p><a href="http://www.quantum-espresso.org/input-syntax/INPUT_PW.html">http://www.quantum-espresso.org/input-syntax/INPUT_PW.html</a></p>
<p>For example, in that webpage, the "eamp" tag reports the units of the electric field in "Hartree" (51.4220632*10^10 V/m). This value for the atomic units of the electric field makes complete sense; however, I do not quite understand the units reported for "efield" tag.</p>
<p>For example, I understand the fact that the value of the "efield" tag should be smaller than that of "eamp" tag; indeed, the value of the "finite electric field" appears to be that of the "eamp" tag divided by the square root of 2. That is: (51.4221*10^10 V/m)/SQRT(2)=36.3609*10^10 V/m.</p>
<p>What I do not understand is the fact that the label "efiled" in the INPUT_PW.html webpage reports the following information:<br>Amplitude of the finite electric field (in Ry a.u.; 1 a.u. = 36.3609*10^10 V/m)</p>
<p>If I follow the above expression, i.e., (51.4221*10^10 V/m)/SQRT(2)=36.3609*10^10 V/m, the units of the "finite electric field" should be Hartrees and not in Rydbergs, right?</p>
<p>Also, in the INPUT_CP.html webpage, the same label "efield" reports the following:<br>Amplitude of the finite electric field (in a.u.; 1 a.u. = 36.3609*10^10 V/m); where, one assumes a.u. to be equal to Hartree.</p>
<p>So, I would like to know if the units of the "finite electric field" in the PW.x code are given in Hartrees or in Rydbergs?</p>
<p>Thanks a lot for your help,<br>S. Sanchez</p>