### [QE-users] Wavefunction Overlap for Different K-space Samplings (repost)

Hi, I’m currently computing wave function overlap of some KS-wave functions produced by QE for monolayer MoS2 with SOC enabled. The wave functions are read with HDF5 in Fortran. However, something is bothering me. When computing < nk | nk’ > = delta_kk’ sum_{G_nk} C*_nk(G_nk) C_nk’(G_nk) , O_nk_nk' = sum_{G_nk} C*_nk(G_nk) C_nk’(G_nk), for k = (0.0 , 0.0 , 0.0) and k’ = (1/3, 1/3, 0) in crystal coordinates, and some fixed band, n (I choose the top valence band in this example), I get wildly different values depending on the k-space sampling. In the equation C_nk and C_nk’ denotes the plane wave coefficients stored in the .hdf5 output files. I’ve attached a figure, displaying the absolute value of O_nk_nk’ for different k-space samplings. I would have imagined, that the values of O_nk_nk’ should either be identical or at least look smooth when plotted against the k-space sampling. Can you clarify on this behaviour? As a note, the wave function stored in your .hdf5 files have four times the length of the number of planewaves (npw). Therefore, I rearrange the wave function as (Fortran version) psi_up_r = psi_k(1:npw_ ,:), psi_up_i = psi_k(npw_+1 :2*npw_ ,:), psi_dw_r = psi_k(2*npw_+1 :3*npw_ ,:), psi_dw_i = psi_k(3*npw_+1 :4*npw_ ,:), where r denotes the real part and vice versa for i. Moreover, I am aware that the G-basis varies for each k-point, and I took care of this as well. Attached figure: https://www.dropbox.com/s/m70kwhg0wir7eh1/wf.png?dl=0 Sorry for reposting, but I did not realise that figures should be attached externally. Kind regards Carl Emil Mørch Nielsen - MSc. Carl Emil Mørch Nielsen Universität Hamburg HARBOR, Geb. 610 Luruper Chaussee 149 D-22761 Hamburg - ___ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users

### [QE-users] Wavefunction Overlap for Different K-space Samplings

[wf.png] Hi, I’m currently computing wave function overlap of some KS-wave functions produced by QE for monolayer MoS2 with SOC enabled. The wave functions are read with HDF5 in Fortran. However, something is bothering me. When computing < nk | nk’ >, for k = (0.0 , 0.0 , 0.0) and k’ = (1/3, 1/3, 0) in crystal coordinates, and some fixed band, n (I choose the top valence band in this example), I get wildly different values depending on the k-space sampling. I’ve attached a figure, displaying the absolute value of < nk | nk’ > for different k-space samplings. I would have imagined, that the values of < nk | nk’ > should either be identical or at least look smooth when plotted against the k-space sampling. Can you clarify on this behaviour? As a note, the wave function stored in your .hdf5 files have four times the length of the number of planewaves (npw). Therefore, I rearrange the wave function as (Fortran version) psi_up_r = psi_k(1:npw_ ,:), psi_up_i = psi_k(npw_+1 :2*npw_ ,:), psi_dw_r = psi_k(2*npw_+1 :3*npw_ ,:), psi_dw_i = psi_k(3*npw_+1 :4*npw_ ,:), where r denotes the real part and vice versa for i. Moreover, I am aware that the G-basis varies for each k-point, and I took care of this as well. Kind regards Carl Emil Mørch Nielsen - MSc. Carl Emil Mørch Nielsen Universität Hamburg HARBOR, Geb. 610 Luruper Chaussee 149 D-22761 Hamburg - ___ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users