Dear Fabian, thank you for your explanation. I tried to get KS matrix using the method you suggested as well, but I wasn't able to do that. I used the following input, but KS matrix files don't get printed. Is there any obvious mishabs in the file? I am using cp2k 7.1 and cp2k.popt. &GLOBAL PROJECT WS2 RUN_TYPE ENERGY PRINT_LEVEL HIGH &END GLOBAL &FORCE_EVAL METHOD Quickstep &DFT BASIS_SET_FILE_NAME BASIS_MOLOPT POTENTIAL_FILE_NAME POTENTIAL &POISSON PERIODIC XYZ &END POISSON &QS EXTRAPOLATION USE_GUESS ! required for K-Point sampling &END QS &SCF SCF_GUESS ATOMIC EPS_SCF 1.0E-6 MAX_SCF 10 ADDED_MOS 2 &DIAGONALIZATION ALGORITHM STANDARD EPS_ADAPT 0.01 &END DIAGONALIZATION &SMEAR ON METHOD FERMI_DIRAC ELECTRONIC_TEMPERATURE [K] 300 &END SMEAR &MIXING METHOD BROYDEN_MIXING ALPHA 0.2 BETA 1.5 NBROYDEN 8 &END MIXING &END SCF &XC &XC_FUNCTIONAL PBE &END XC_FUNCTIONAL &END XC &KPOINTS SCHEME MONKHORST-PACK 6 6 1 SYMMETRY OFF WAVEFUNCTIONS REAL FULL_GRID .TRUE. PARALLEL_GROUP_SIZE 0 VERBOSE .TRUE. &END KPOINTS &PRINT &BAND_STRUCTURE ADDED_MOS 2 FILE_NAME WS2.bs &KPOINT_SET UNITS B_VECTOR SPECIAL_POINT 0 0 0 #GAMA SPECIAL_POINT 0.5 0 0 #M NPOINTS 20 &END &END BAND_STRUCTURE &KS_CSR_WRITE HIGH FILENAME ./KS.dat &END KS_CSR_WRITE &END PRINT &END DFT &SUBSYS &CELL A [angstrom] 2.727930196922421 -1.574726113675518 0 B [angstrom] 2.727923196921916 1.574726113675518 0 C [angstrom] 0 0 15 PERIODIC XY MULTIPLE_UNIT_CELL 1 1 1 &END CELL &TOPOLOGY MULTIPLE_UNIT_CELL 1 1 1 &END TOPOLOGY &COORD S 1.818565911277700 0 0 W 0 0 1.5693444632870293 S 1.818565911277700 0 3.138691180574223 &END &KIND W ELEMENT W BASIS_SET SZV-MOLOPT-SR-GTH POTENTIAL GTH-PBE &END KIND &KIND S ELEMENT S BASIS_SET SZV-MOLOPT-SR-GTH POTENTIAL GTH-PBE &END KIND &END SUBSYS &END FORCE_EVAL Many thanks, Elaheh <div class="gmail_quote"><div dir="auto" class="gmail_attr">On Thursday, December 3, 2020 at 1:57:18 PM UTC+1 fa...@gmail.com wrote: </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div>Dear Elaheh,</div><div> </div><div>I don't know how to print the indices easily. But you can use DFT%PRINT%KS_CSR_WRITE and DFT%PRINT%S_CSR_WRITE to write the Hamiltonain and overlap matrices to the disk. If you use k-points a file for each k-point is created in the ordering given in the output file.</div><div> </div><div>Cheers,</div><div>Fabian </div> <div class="gmail_quote"><div dir="auto" class="gmail_attr">On Wednesday, 2 December 2020 at 12:07:10 UTC+1 <a href data-email-masked rel="nofollow">akho...@gmail.com</a> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Hello,</div><div>I have extracted the Kohn Sham Hamiltonian using &AO_MATRICES HIGH ----> KOHN_SHAM_MATRIX .TRUE. , in order to plot the band structure myself using the Hamiltonian matrix. However, the format of the output is not clear to me. I believe each block of Hamiltonian corresponds to the interaction of the primary cell with a specific neigboring cell. but it is not specified in the output file which block is related to which neighboring cell, i.e. what are the cell indices corresponding to each block. Is there any way that I can access the cell indices related to each Hamiltonian block?</div><div>I would greatly appreciate your help.</div><div>kind regards,</div><div>Elaheh Akhoundi</div></blockquote></div></blockquote></div>