Sir,<br><br>Good evening.<br><br>I think I was unable to convey my message correctly.<br><br>Kindly go through the input file below.<br>---------------------------------------------------------------------------------------------------------<br>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++<br> &CONTROL<br> title = Graphene mono layer ,<br> calculation = 'relax' ,<br> restart_mode = 'from_scratch' ,<br>
outdir = '/root/tmp/' ,<br> pseudo_dir = '/root/Desktop/QUANTUM_ESPRESSO/pseudo/' ,<br> prefix = graphene ,<br> disk_io = 'default' ,<br>
verbosity = 'default' ,<br> etot_conv_thr = 1.D-4 ,<br> forc_conv_thr = 1.D-3 ,<br> nstep = 50 ,<br> dt = 40 ,<br> /<br>
&SYSTEM<br> ibrav = 0,<br> <span style="background-color: rgb(255, 255, 0);"> celldm(1) = 1.0000000,</span><br style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 0);"> celldm(2) = 1.0000000,</span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"> celldm(3) = 0.5000000,</span><br style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 0);"> nat = 32,</span><br>
ntyp = 1,<br> ecutwfc = 50 ,<br> ecutrho = 400 ,<br> occupations = 'smearing' ,<br> smearing = 'methfessel-paxton' ,<br>
nspin = 1 ,<br> lda_plus_u = .false. ,<br> /<br> &ELECTRONS<br> electron_maxstep = 300,<br> conv_thr = 1.0d-8 ,<br> mixing_mode = 'plain' ,<br>
mixing_beta = 0.5 ,<br> diagonalization = 'cg' ,<br> diago_cg_maxiter = 50,<br> /<br> &IONS<br> /<br>CELL_PARAMETERS <br> <span style="background-color: rgb(255, 255, 0);">16.121319540 9.383047808 0.000000000 </span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"> 0.000000000 18.658162370 0.000000000 </span><br style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 0);"> 0.000000000 0.000000000 56.689342400 </span><br>
ATOMIC_SPECIES<br> C 12.01070 C.pbe-van_bm.UPF <br>ATOMIC_POSITIONS angstrom <br> C 2.891630000 7.402190000 2.000000000 <br> C 3.592920000 8.638320000 2.000000000 <br> C 3.603490000 6.167020000 2.000000000 <br>
C 5.018600000 8.645010000 2.000000000 <br> C 5.021500000 6.165980000 2.000000000 <br> C 5.733020000 7.405220000 2.000000000 <br> C 1.471840000 7.396160000 2.000000000 <br>
C 2.891120000 9.870660000 2.000000000 <br> C 2.894710000 4.932640000 2.000000000 <br> C 5.733190000 9.888500000 2.000000000 <br> C 5.736430000 4.941300000 2.000000000 <br>
C 7.163480000 7.412030000 2.000000000 <br> C 1.474740000 4.926900000 2.000000000 <br> C 0.762281000 8.627830000 2.000000000 <br> C 0.763134000 6.161720000 2.000000000 <br>
C 1.471500000 9.863350000 2.000000000 <br> C 3.603410000 11.109500000 2.000000000 <br> C 5.021240000 11.123900000 2.000000000 <br> C 3.605120000 3.701560000 2.000000000 <br>
C 5.026450000 3.707890000 2.000000000 <br> C 7.878070000 8.655320000 2.000000000 <br> C 7.163730000 9.894970000 2.000000000 <br> C 7.162030000 4.948140000 2.000000000 <br>
C 7.876190000 6.176770000 2.000000000 <br> C 5.736340000 12.352200000 2.000000000 <br> C 0.772689000 3.691020000 2.000000000 <br> C 0.762793000 1.220030000 2.000000000 <br>
C 7.876450000 11.133700000 2.000000000 <br> C 7.162030000 12.358700000 2.000000000 <br> C 7.872010000 13.592200000 2.000000000 <br> C 2.894790000 2.466190000 2.000000000 <br>
C 1.474820000 2.458780000 2.000000000 <br>K_POINTS automatic <br> 6 6 1 1 1 1 <br><br>---------------------------------------------------------------------------------------------------------<br>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++<br>
<br>I am desparately trying to understand how to determine:<br>1. The <br><span style="background-color: rgb(255, 255, 0);">CELL_PARAMETERS </span><br style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 0);">
16.121319540 9.383047808 0.000000000 </span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"> 0.000000000 18.658162370 0.000000000 </span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"> 0.000000000 0.000000000 56.689342400 </span><br style="background-color: rgb(255, 255, 255);">(or how are they determined in this case) - This is again a copy of earlier post.<br>
2. <span style="background-color: rgb(255, 255, 255);">The <span style="background-color: rgb(255, 255, 0);">celldm(1) = 1.0000000,</span></span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"> celldm(2) = 1.0000000,</span><br style="background-color: rgb(255, 255, 0);">
<span style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 0);"> celldm(3) = 0.5000000,</span><br style="background-color: rgb(255, 255, 255);"><span style="background-color: rgb(255, 255, 255);"> How do I fix them.<br>
Is there any software and/or technique to do this? or Is there any mathematical relation that would be able to provide me these values.<br>The cell parameters are given to a precision upto 9th decimal place.<br><br>Secondly, the celldm(3) =0.5, does it mean that it would divide the value 56.689342400 by 2 and can similar logic be applied to celldm(1) and celldm(2)?<br>
Thirdly, if I view the geometry in XcrySDen, it show vacuum layers in Z direction, but no gap/vacuum in x and y direction? </span></span><span style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 255);">I have seen this in many papers published till date and is trying to understand these things.</span></span><br>
<span style="background-color: rgb(255, 255, 0);"><span style="background-color: rgb(255, 255, 255);">Doesn't the adjacent supercell (in x and y direction) interact with the supercell under consideration?<br>Also is there relation between the co-ordinates of the atom, the CELL PARAMETERS and celldm()?<br>
<br>I hereby request you to kindly help me in this regard.<br><br>Deepak Thakur<br>Research Student<br>Swami Ramanand Teerth Marathwada University, <br>Vishnupuri, Nanded, <br>Maharashtra, <br>India.<br></span></span>