<div dir="ltr"><div>Dear PWSCF users,<br></div> I am trying to find out activation energy barrier using the following input file:<br><div><br>BEGIN<br>BEGIN_PATH_INPUT<br>&PATH<br> restart_mode = 'from_scratch'<br>
string_method = 'neb',<br> nstep_path = 20,<br> ds = 2.D0,<br> opt_scheme = "broyden",<br> num_of_images = 13,<br> k_max = 0.3D0,<br> k_min = 0.2D0,<br>
path_thr = 0.1D0,<br> CI_scheme = "auto",<br>/<br>END_PATH_INPUT<br>BEGIN_ENGINE_INPUT<br>&CONTROL<br> outdir = './temp' ,<br> pseudo_dir = '/lustre/home/pati/dibyajyoti/pseudo' ,<br>
prefix = 'Pt' ,<br><br><br>/<br>&SYSTEM<br> ibrav = 0,<br> celldm(1) = 1.8903<br> nat = 10,<br> ntyp = 3,<br>
ecutwfc = 30 ,<br> ecutrho = 300 ,<br> occupations = 'smearing' ,<br> smearing = 'marzari-vanderbilt' ,<br> degauss = 0.01<br>
nspin = 2<br> starting_magnetization = 0.5<br> nbnd = 43<br><br>/<br> &ELECTRONS<br> electron_maxstep = 1000 ,<br> conv_thr = 1.0d-10<br>
mixing_beta = 0.2 ,<br> mixing_ndim = 10<br> mixing_mode = 'local-TF',<br><br>/<br> &IONS<br> upscale = 100 ,<br><br>/<br>ATOMIC_SPECIES<br>Pt 195.084 Pt.pbe-n-rrkjus.UPF<br>
C 12.0107 C.pbe-rrkjus.UPF<br>O 15.9994 O.pbe-rrkjus.UPF<br>BEGIN_POSITIONS<br>FIRST_IMAGE<br>ATOMIC_POSITIONS angstrom<br></div><div>Pt 1.850700972 1.443626858 0.453046673<br></div><div>Pt 0.943102964 -0.609627043 1.659354547<br>
</div><div>Pt -0.798952486 -1.224214284 -0.100158908<br></div><div>Pt -2.211088061 0.532477856 -1.210633206<br></div><div>Pt 0.270075228 0.834135105 -1.601571936<br></div><div>Pt 1.835978831 -0.859969770 -0.656743659<br>
</div><div>Pt -0.639803936 1.200085717 0.697528230<br></div><div>C -1.060512280 -2.400253027 1.556970754<br>O -0.145487591 -2.112102579 2.495594831<br>O -1.947109262 -3.229564672 1.624429613<br>
LAST_IMAGE<br>ATOMIC_POSITIONS angstrom<br></div><div>Pt 2.264303115 1.248048227 -0.373892267<br></div><div>Pt 1.233936451 0.429684066 1.664068322<br></div><div>Pt -0.599847604 -1.184402943 0.479361678<br>
</div><div>Pt -2.264784842 0.422857144 -0.859094096<br></div><div>Pt 0.154170583 0.511311728 -1.355526205<br></div><div>Pt 1.788026807 -1.237306598 -0.282147524<br></div><div>Pt -1.090091750 1.304671686 1.067520981<br>
</div><div>C -1.183511240 -2.839811696 1.082397758<br>O -0.053539990 1.362720752 2.762505051<br>O -1.560582512 -3.882441918 1.450309452<br><br>END_POSITIONS<br>K_POINTS gamma<br><br>CELL_PARAMETERS<br>
15.00 0.000 0.000<br>0.000 15.000 0.000<br>0.000 0.000 15.0000<br>END_ENGINE_INPUT<br>END<br><br></div><div>Here I have optimized the initial and final configuration using the same above-mentioned parameters.<br><br>
</div><div>Now my output file is as follows:<br> tcpu = 0.5 self-consistency for image 1<br> tcpu = 241.7 self-consistency for image 2<br> tcpu = 488.9 self-consistency for image 3<br>
tcpu = 1528.9 self-consistency for image 4<br> tcpu = 1946.8 self-consistency for image 5<br> tcpu = 2173.8 self-consistency for image 6<br> tcpu = 2394.8 self-consistency for image 7<br>
tcpu = 2606.1 self-consistency for image 8<br> tcpu = 2818.9 self-consistency for image 9<br> tcpu = 3035.4 self-consistency for image 10<br> tcpu = 3240.4 self-consistency for image 11<br>
tcpu = 3451.0 self-consistency for image 12<br> tcpu = 3652.6 self-consistency for image 13<br><br> activation energy (->) = 3.653530 eV<br> activation energy (<-) = 4.304438 eV<br>
<br>
image energy (eV) error (eV/A) frozen<br><br> 1 -6602.5486692 0.022305 T<br> 2 -6602.0377242 1.565266 F<br> 3 -6601.0045584 3.796768 F<br>
4 -6600.1369964 6.450495 F<br> 5 -6599.5968046 9.161897 F<br> 6 -6599.1340788 12.357714 F<br> 7 -6598.8951396 15.478612 F<br>
8 -6599.1668824 15.915268 F<br> 9 -6600.0106926 13.371867 F<br> 10 -6601.1786031 9.108378 F<br> 11 -6602.2646119 4.906636 F<br>
12 -6602.9623766 2.160567 F<br> 13 -6603.1995776 0.022152 T<br><br> climbing image = 7<br><br> path length = 7.695 bohr<br> inter-image distance = 0.641 bohr<br>
<br> ------------------------------ iteration 2 ------------------------------<br><br> tcpu = 3850.9 self-consistency for image 2<br> tcpu = 4044.8 self-consistency for image 3<br> tcpu = 4238.3 self-consistency for image 4<br>
tcpu = 4683.9 self-consistency for image 5<br> tcpu = 4895.3 self-consistency for image 6<br> tcpu = 5105.9 self-consistency for image 7<br> tcpu = 5408.6 self-consistency for image 8<br>
tcpu = 5620.6 self-consistency for image 9<br> tcpu = 5849.9 self-consistency for image 10<br> tcpu = 6057.8 self-consistency for image 11<br> tcpu = 6230.2 self-consistency for image 12<br>
<br> activation energy (->) = 2.062313 eV<br> activation energy (<-) = 2.713222 eV<br> -----------------------------------------<br>
------------------------------------------<br><br></div><div>GOING ON<br><br>----------------------------------------------<br>--------------------------------------------------<br> ------------------------------ iteration 7 ------------------------------<br>
<br> tcpu = 18797.0 self-consistency for image 2<br> tcpu = 18990.2 self-consistency for image 3<br> tcpu = 19167.7 self-consistency for image 4<br> tcpu = 19373.5 self-consistency for image 5<br>
tcpu = 19550.3 self-consistency for image 6<br> tcpu = 19735.4 self-consistency for image 7<br> tcpu = 19928.9 self-consistency for image 8<br> tcpu = 20208.5 self-consistency for image 9<br>
tcpu = 20414.3 self-consistency for image 10<br> tcpu = 20601.5 self-consistency for image 11<br> tcpu = 20797.3 self-consistency for image 12<br><br> activation energy (->) = 0.870973 eV<br>
activation energy (<-) = 1.521881 eV<br><br> image energy (eV) error (eV/A) frozen<br><br> 1 -6602.5486692 0.022305 T<br> 2 -6602.3736900 0.418040 F<br>
3 -6602.0387523 0.866756 F<br> 4 -6602.4903013 1.278867 F<br> 5 -6602.6203749 1.591716 F<br> 6 -6602.4366766 1.877891 F<br>
7 -6602.0438039 6.617516 F<br> 8 -6601.6776962 9.883500 F<br> 9 -6602.1051387 9.603478 F<br> 10 -6602.5765272 7.925611 F<br>
11 -6602.9662496 4.279627 F<br> 12 -6603.1521927 1.394729 F<br> 13 -6603.1995776 0.022152 T<br><br> climbing image = 8<br>
<br> path length = 8.676 bohr<br> inter-image distance = 0.723 bohr<br><br> ------------------------------ iteration 8 ------------------------------<br><br> tcpu = 20970.9 self-consistency for image 2<br>
tcpu = 21179.9 self-consistency for image 3<br> tcpu = 21361.6 self-consistency for image 4<br> tcpu = 21610.7 self-consistency for image 5<br> tcpu = 21795.2 self-consistency for image 6<br>
tcpu = 21975.4 self-consistency for image 7<br> tcpu = 22174.0 self-consistency for image 8<br> tcpu = 22394.2 self-consistency for image 9<br> tcpu = 22588.3 self-consistency for image 10<br>
tcpu = 22790.2 self-consistency for image 11<br> tcpu = 22963.6 self-consistency for image 12<br><br> activation energy (->) = 0.428213 eV<br> activation energy (<-) = 1.079121 eV<br>
<br> image energy (eV) error (eV/A) frozen<br><br> 1 -6602.5486692 0.022305 T<br> 2 -6602.3935880 0.506242 F<br> 3 -6602.1204563 1.078653 F<br>
4 -6602.7001074 1.279534 F<br> 5 -6602.8317653 1.500866 F<br> 6 -6602.6432007 0.976795 F<br> 7 -6602.4268968 1.081261 F<br>
8 -6602.2149366 2.153274 F<br> 9 -6602.6011231 1.898303 F<br> 10 -6602.9175545 1.150728 F<br> 11 -6603.0816841 0.278682 F<br>
12 -6603.1673752 0.239983 F<br> 13 -6603.1995776 0.022152 T<br><br> climbing image = 3<br><br> path length = 9.060 bohr<br> inter-image distance = 0.755 bohr<br>
<br></div><div> So, here in the last iteration it is found that image 4, 5 and 6 are lower in energy than the initial one.<br></div><div>But how is it possible?<br></div><div>What is the wrong in the procedure?<br><br>
</div><div>Thank you very much<br><br></div><div>Regards<br></div><div> Pallavi Bothra<br></div><div>Graduate student<br></div><div>JNCASR, Bangalore<br></div><div>India <br>
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