[QE-users] E-field units inconsistent

[Joseph Frimpong]

Dear Users and Developers,


I need clarifications on the finite e-field conversion factor for 1 a.u found on the input file description at https://www.quantum-espresso.org/Doc/INPUT_PW.html<https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm840> and in the source code at $QEDIR/PW/src/extfield.f90.



Reading the input file description online: under “efield”, says in Ry a.u.; 1 a.u. = 36.3609*10^10 V/m



We know E-field in a.u. is 5.14220674763(78)×10^11 V⋅m−1 from https://en.wikipedia.org/wiki/Hartree_atomic_units; which means in Ry a.u., it should be 51.422/2 = 25.711, but the 36.3609 is actually 51.422/sqrt(2).



In the source code: $QEDIR/PW/src/extfield.f90, line #38, in the variable “eamp”, the comment says “(1 a.u. = 51.44 10^11 V/m)” which matches the Wikipedia result but not the INPUT_PW webpage.


Which one is correct?  Can someone please resolve this confusion?



Thanks for your time.


-----------------------------------------

Joseph Frimpong

Graduate Research Assistant

Department of Chemistry

Wayne State University



-----------------------------------------

Joseph Frimpong

Graduate Research Assistant

Liu's Group

Department of Chemistry

Wayne State University

5101 Cass Ave, Detroit, MI 48202

Phone: (313) 577-0552

https://liugroupwsu.weebly.com/
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