[CP2K-user] [CP2K:22233] Re: MOMENTS and KPOINTS

[Shridhar Shanbhag]

Thanks for the question. The dipole matrix elements with k-point sampling 
are available under the section titled "Periodic Dipole Matrix Elements" in 
the output file as shown below.

 !-----------------------------------------------------------------------------!
                     Periodic Dipole Matrix Elements

 Kpoint:  1 , kx:   -0.375000, ky:   -0.375000, kz:    0.000000
   kp  n  m  Re(dx_nm)  Im(dx_nm)  Re(dy_nm)  Im(dy_nm)  Re(dz_nm) 
 Im(dz_nm)

Under this section you will find a table that gives the real and imaginary 
x, y and z components of the Bloch-state dipole matrix elements:

μ_nm(k) = <u_nk | ∇_k | u_mk>

computed for each k-point provided by the user along a line or a grid.

These are transition dipole matrix elements between Bloch states. I am not 
sure what you are referring to as the total crystal dipole moment. The 
total dipole moment for a system with charge separation is calculated as 
the vector sum of all individual molecular or bond dipole moments within 
the crystal structure: μ=Σ q_i *d*_i. That quantity is not calculated here.

Hope this helps.

Kind regards,
Shridhar 
On Tuesday, May 12, 2026 at 4:47:58 PM UTC+2 pierre.an... at gmail.com wrote:

> Dear all,
>
> The ability to access dipole moments with KPOINTS is a major addition to 
> CP2K. Still, I'm confused as to where the dipole moment actually is in the 
> output file.
>
> I tried the test file provided with CP2K 2026.1, but I cannot find the 
> dipole moment for each k-point or for the crystal.
>
> Could you please let me know where this information is? I'm particularly 
> interested in the total crystal dipole moment.
>
> Kind regards
> Pierre 
>
>

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