[Pw_forum] Raman calculation of graphyne
Ari P Seitsonen
Ari.P.Seitsonen at iki.fi
Thu Jun 23 07:08:48 CEST 2016
Dear Barnali,
The symmetries stem from the self-consistent calculation, so the problem
is there. Indeed it looks from the few coordinates in the input that you
provided that they are not precisely - up to some 4-5 digits on the
symmetric positions like 0.5; thus 'pw.x' does not consider these as
symmetries and all the modes become labelled with the basic symmetry "A".
Please try symmetrising the coordinates, checking already in the output of
'pw.x' that you have the symmetry requested.
Greetings from Paris,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
On Thu, 23 Jun 2016, Barnali Bhattacharya wrote:
>
> Dear Sir/Madam
>
> I am trying to reproduce the Raman spectra of graphyne system reported by Zhang et al [J. Phys. Chem. C, 2016, 120 (19), pp 10605–10613].
> In my calculated spectra, I have found the Raman peaks are located more or less on same frequency as observed in the paper of Zhang et al. The position of the Raman peaks are given below-
>
> …………………
>
> # mode [cm-1] [THz] IR Raman depol.fact
>
> 1 -0.00 -0.0000 0.0000 0.0000 0.7265
>
> 2 -0.00 -0.0000 0.0000 0.0000 0.7498
>
> 3 0.00 0.0000 0.0000 0.0001 0.5641
>
> 4 180.32 5.4057 0.0000 1.4898 0.2967
>
> 5 180.47 5.4103 0.0000 1.5604 0.7466
>
> 6 232.43 6.9680 0.0000 51.4183 0.7500
>
> 7 232.84 6.9804 0.0000 59.4666 0.7500
>
> 8 249.23 7.4716 0.0000 955497.8547 0.1945
>
> 9 333.27 9.9912 0.0276 6.5036 0.6017
>
> 10 401.52 12.0373 0.0000 0.0027 0.3409
>
> 11 413.75 12.4038 0.0589 0.0026 0.5983
>
> 12 414.29 12.4201 0.0586 0.0128 0.2304
>
> 13 465.96 13.9692 0.0003 0.0051 0.7477
>
> 14 506.14 15.1738 0.0000 4286930.6335 0.1763
>
> 15 506.61 15.1879 0.0000 153395.9276 0.3020
>
> 16 557.47 16.7124 0.0001 3677.4093 0.7500
>
> 17 557.63 16.7175 0.0001 4445.0962 0.7500
>
> 18 672.04 20.1471 0.0000 0.0257 0.6204
>
> 19 679.01 20.3562 0.0000 5.2659 0.6276
>
> 20 679.11 20.3593 0.0000 10.5107 0.2863
>
> 21 788.70 23.6446 0.0000 14647549.8132 0.1986
>
> 22 793.96 23.8025 0.0000 0.0232 0.7498
>
> 23 948.26 28.4280 0.0000 3919030.7925 0.2311
>
> 24 948.36 28.4312 0.0000 1167947.1815 0.2501
>
> 25 1059.37 31.7591 3.1810 4.7302 0.2109
>
> 26 1059.64 31.7672 3.1760 0.1304 0.2298
>
> 27 1205.12 36.1285 0.0000 56577350.6847 0.2012
>
> 28 1388.64 41.6303 0.0000 0.0043 0.6020
>
> 29 1465.22 43.9261 0.0000 710764.1488 0.6076
>
> 30 1465.26 43.9274 0.0000 1596968.3457 0.3793
>
> 31 1482.91 44.4565 0.0018 4.9641 0.3255
>
> 32 1501.10 45.0019 23.8090 1.7968 0.3140
>
> 33 1501.37 45.0098 23.7976 0.3151 0.3348
>
> 34 2191.33 65.6945 0.0000 162172387.6538 0.1964
>
> 35 2230.26 66.8616 0.0000 3616106.5565 0.1860
>
> 36 2231.11 66.8870 0.0000 2730839.0109 0.1988
>
> ……………………………………………………………………….
>
> But the problem arises in the case of mode symmetry and irreducible representation calculation.
> I am not able to generate same irreducible representation like Zhang has got.
> Of course, I have missed some technique or something wrong with my understanding.
> My calculated irreducible representations are presented below-
>
> ……………………..
>
> Mode symmetry, C_1 (1) point group:
>
>
>
> freq ( 1 - 1) = 0.6 [cm-1] --> A I+R
>
> freq ( 2 - 2) = 3.2 [cm-1] --> A I+R
>
> freq ( 3 - 3) = 17.3 [cm-1] --> A I+R
>
> freq ( 4 - 4) = 180.3 [cm-1] --> A I+R
>
> freq ( 5 - 5) = 180.5 [cm-1] --> A I+R
>
> freq ( 6 - 6) = 232.4 [cm-1] --> A I+R
>
> freq ( 7 - 7) = 232.8 [cm-1] --> A I+R
>
> freq ( 8 - 8) = 249.2 [cm-1] --> A I+R
>
> freq ( 9 - 9) = 333.3 [cm-1] --> A I+R
>
> freq ( 10 - 10) = 401.5 [cm-1] --> A I+R
>
> freq ( 11 - 11) = 413.7 [cm-1] --> A I+R
>
> freq ( 12 - 12) = 414.3 [cm-1] --> A I+R
>
> freq ( 13 - 13) = 466.0 [cm-1] --> A I+R
>
> freq ( 14 - 14) = 506.1 [cm-1] --> A I+R
>
> freq ( 15 - 15) = 506.6 [cm-1] --> A I+R
>
> freq ( 16 - 16) = 557.5 [cm-1] --> A I+R
>
> freq ( 17 - 17) = 557.6 [cm-1] --> A I+R
>
> freq ( 18 - 18) = 672.0 [cm-1] --> A I+R
>
> freq ( 19 - 19) = 679.0 [cm-1] --> A I+R
>
> freq ( 20 - 20) = 679.1 [cm-1] --> A I+R
>
> freq ( 21 - 21) = 788.7 [cm-1] --> A I+R
>
> freq ( 22 - 22) = 794.0 [cm-1] --> A I+R
>
> freq ( 23 - 23) = 948.3 [cm-1] --> A I+R
>
> freq ( 24 - 24) = 948.4 [cm-1] --> A I+R
>
> freq ( 25 - 25) = 1059.4 [cm-1] --> A I+R
>
> freq ( 26 - 26) = 1059.6 [cm-1] --> A I+R
>
> freq ( 27 - 27) = 1205.1 [cm-1] --> A I+R
>
> freq ( 28 - 28) = 1388.6 [cm-1] --> A I+R
>
> freq ( 29 - 29) = 1465.2 [cm-1] --> A I+R
>
> freq ( 30 - 30) = 1465.3 [cm-1] --> A I+R
>
> freq ( 31 - 31) = 1482.9 [cm-1] --> A I+R
>
> freq ( 32 - 32) = 1501.1 [cm-1] --> A I+R
>
> freq ( 33 - 33) = 1501.4 [cm-1] --> A I+R
>
> freq ( 34 - 34) = 2191.3 [cm-1] --> A I+R
>
> freq ( 35 - 35) = 2230.3 [cm-1] --> A I+R
>
> freq ( 36 - 36) = 2231.1 [cm-1] --> A I+R
>
> ……………………………………..
>
> My questions are
>
> 1. How can I generate the correct irreducible representation for graphyne? Please suggest me the correct path.
>
> Here I have attached the input files (grapyne.scf.in and graphyne.phonon.in) for details information.
>
> 2. I have calculated the Raman spectra of graphene with the same procedure and found exact irreducible representation. Why problem arises in the case of graphyne? Because graphene and
> graphyne have same hexagonal symmetry.
>
>
> I am waiting for any reply. Any help will be thankfully acknowledged.
>
>
>
> Thanking you.
>
>
>
> Sincerely
>
> Barnali Bhattacharya
>
> Ph.D student
>
> Department of physics
>
> Assam University
>
>
>
>
>
>
>
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