Body Centered Tetragonal Carbon

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arjunvarmar
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Joined: Tue Jun 05, 2018 3:51 pm

Body Centered Tetragonal Carbon

Post by arjunvarmar » Mon Aug 06, 2018 12:43 pm

We have been trying to optimize the lattice parameters of metastable Carbon (BCT-8). It is in space group 139 with Wyckoff positions 8h. We have tried this by modifying two of the ABINIT input files. One is the White Tin (BCT Space Group 141) and the other is the ABINIT AlAs (Hexagonal) lattice parameter optimization using BFGS algorithm. The links are given below:

1. https://docs.abinit.org/tests/v5/Input/t77.in

2. https://docs.abinit.org/tests/tutorespf ... elast_1.in


We modified the above input files. The second input file gives the wrong space group (#69) Face centered orthorhombic. In the first case, the lattice parameters and rprim values were not as expected. The output values of parameters that were relevant are given below:
#################################################################################################

== END DATASET(S) ==============================================================
================================================================================

-outvars: echo values of variables after computation --------
acell1 6.2950344795E+00 6.2950344795E+00 6.2950344795E+00 Bohr
acell2 6.2950344462E+00 6.2950344462E+00 6.2950344462E+00 Bohr
amu 1.20110000E+01
.
.
.
rprim1 -6.5531190797E-01 6.5531190797E-01 3.7567619906E-01
6.5531190797E-01 -6.5531190797E-01 3.7567619906E-01
6.5531190797E-01 6.5531190797E-01 -3.7567619906E-01
rprim2 -6.5531190755E-01 6.5531190755E-01 3.7567620053E-01
6.5531190755E-01 -6.5531190755E-01 3.7567620053E-01
6.5531190755E-01 6.5531190755E-01 -3.7567620053E-01
#################################################################################################

The full input files are attached below. We have tried many other combinations for the calculation but all of them had similar problems. We would like to know how to proceed further?
Attachments
telast_1.in
Modified from White tin Input File
(1.67 KiB) Downloaded 120 times
telast_1.in
Modified from AlAs input file
(4.48 KiB) Downloaded 121 times

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