[Pw_forum] cohesive energy of C60
Jose Manuel Napoles Duarte
napolesd at cactus.iico.uaslp.mx
Fri Jan 12 21:30:47 CET 2007
Dear pwscf users,
I am trying to do a test pwscf calculation of fullerene C60 in a FCC
bravais lattice. I have the reference of Saito and Oshiyama (PRL 66 ,2637
(1991)) and that of Troullier and Martins (PRB 46,1754 (1992)) where both
groups found a cohesive energy of 1.6 eV. However in a preliminar result I
have found the following energy for fcc c60 with lattice parameter
(a_0)= 26.7248 a.u. (equivalent to a_0= 14.142 Angstrom):
> grep ! c60fccgeom10.out
! total energy = -683.97694515 ryd
and for the isolated molecule:
grep ! c60damp.out
No symmetry!
! total energy = -683.91687200 ryd
! total energy = -683.91692937 ryd
! total energy = -683.91700216 ryd
! total energy = -683.91706827 ryd
! total energy = -683.91702891 ryd
! total energy = -683.91705256 ryd
! total energy = -683.91706654 ryd
! total energy = -683.91708083 ryd
! total energy = -683.91707390 ryd
! total energy = -683.91708201 ryd
! total energy = -683.91708245 ryd
! total energy = -683.91708268 ryd
! total energy = -683.91708291 ryd
! total energy = -683.91708326 ryd
! total energy = -683.91708337 ryd
! total energy = -683.91708436 ryd
! total energy = -683.91708405 ryd
! total energy = -683.91708381 ryd
! total energy = -683.91708464 ryd
! total energy = -683.91708457 ryd
! total energy = -683.91708430 ryd
So giving a cohesive energy of 0.81410756 eV which I guess is about 1/2 of
the energy reported in the references given above. I really don`t
understend what is happening.
The C60 molecule is set such that each axis crosses a double bond at the
midpoint.
Below is the input file for the fcc-C60. For the isolated molecule I first
do a damped dynamics optimization.
thanks
J. M. Napoles
PhD student
Instituto de Investigacion en Comunicacion Optica
Universidad Autonoma de San Luis Potosi
San Luis Potosi, Mexico
/
&control
calculation='scf'
restart_mode='from_scratch'
prefix='C60fccgeom'
pseudo_dir=' '
outdir=' '
/
&system
ibrav=2, nat=60, ntyp=1,celldm(1)=26.7247738
ecutwfc = 50.0, ecutrho = 300.0
occupations='smearing', smearing='methfessel-paxton', degauss=0.005
/
&electrons
conv_thr = 1.0d-6
mixing_beta = 0.5
/
ATOMIC_SPECIES
C 12.0107 C.pz-rrkjus.UPF
ATOMIC_POSITIONS {angstrom}
C 1.407368348 -1.169270087 -2.996352523
C 1.155000914 -2.998721394 1.414231172
C -2.569868573 0.727048774 2.278942600
C -1.407369748 1.169270123 2.996354503
C -2.572934630 -0.708858874 2.281123936
C -1.168248777 -2.993711628 1.413850706
C -1.154999556 2.998716434 -1.414235192
C 2.569873218 -0.727045947 -2.278934183
C -3.443475569 -0.684030397 0.000528040
C -2.285795345 -2.567271017 -0.714319855
C -1.411460082 -1.163183560 -2.996790774
C 2.569183053 -0.719996621 2.281933017
C 2.572942818 0.708860996 -2.281117431
C 0.691950027 -0.006743425 -3.441895530
C 0.712638046 -2.278049679 2.574700204
C -0.712641482 2.278048778 -2.574700904
C -0.691960543 0.006744382 3.441896564
C 2.275044288 -2.577090608 -0.713619986
C -2.275043517 2.577094390 0.713619895
C -1.412387498 -1.153994791 2.999932296
C -0.723266366 -2.274967859 2.574471677
C 2.572243493 0.715908748 2.279712906
C -3.001182866 -1.404764735 -1.159915160
C 1.155438733 -3.003036722 -1.404638851
C -2.572239887 -0.715911865 -2.279718564
C 1.412386937 1.153998869 -2.999931150
C -2.995166398 1.414092648 -1.164264062
C 0.722467030 2.282840618 2.567674821
C -0.007446490 -3.440967562 0.696724153
C 3.440539698 -0.698842016 0.001593642
C -3.440541125 0.698844548 -0.001591405
C -1.167819674 -2.998024268 -1.404977765
C -0.722472878 -2.282835618 -2.567674762
C 2.995170011 -1.414092306 1.164257891
C 0.723259638 2.274974525 -2.574473179
C -1.155437472 3.003038299 1.404638985
C 3.001187729 1.404761625 1.159913217
C 1.167819111 2.998024849 1.404975960
C 2.995521908 -1.417677189 -1.158979906
C 1.168247528 2.993715403 -1.413852038
C 0.007444736 3.440964394 -0.696728588
C -3.001537554 -1.401174161 1.163337969
C 1.406467715 -1.160078807 3.000371626
C -0.690908691 -0.003781257 -3.442111538
C -2.286027765 -2.565072224 0.721571219
C 3.001546058 1.401171970 -1.163329086
C -1.406469268 1.160075629 -3.000369224
C 0.690898738 0.003779607 3.442113424
C -2.274832893 2.574892089 -0.722292146
C 2.286031105 2.565069342 -0.721567056
C 0.007232021 3.443069261 0.686129858
C 2.285800339 2.567266719 0.714321873
C 1.411455172 1.163183237 2.996789095
C -2.569178195 0.719996609 -2.281934935
C 3.443475635 0.684027870 -0.000523865
C -2.995519741 1.417679476 1.158987181
C 2.274836356 -2.574893690 0.722285126
C 0.713422702 -2.285919833 -2.567457257
C -0.713428440 2.285919456 2.567457625
C -0.007232083 -3.443071526 -0.686134267
K_POINTS {automatic}
6 6 6 0 0 0
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