关注：

1) Raman光谱的产生原理

2) Raman光谱的实验测量与理论方法

3) 什么样 的材料具有Raman 活性，金属呢？

持续整理中....

题记：Raman活性支如何判断

Experimentaldiscrimination between Co₂Si and Ni₂In phases requires combinationof XRD and Raman spectroscopy: the cotunnite phase has 18 possible Raman-active modes (6Ag+6B_1g+3B_2g+3B_3g),

the Co₂Si phase also has 18 possible Raman modes, but not completely the same as the cotunnite phase,17 and thehexagonal Ni₂In phase has only 2 possible Raman modes (2Eg).

Recently, the Ni₂In phase in CaF₂, SrF₂and BaF₂ compounds have been observed by powder XRD 17,18 and Raman.17 T

herefore it is highly possible that in the near future we can identify these post-cotunnite phases in actinide dioxides experimentally

后处理计算过程：


1. 生成力常数（FORCE_CONSTANTS），使用命令% phonopy --fc
vasprun.xml

2. Raman谱及不可约表示

    建立Raman文件夹，拷贝初始的单胞POSCAR-unitcell、FORCE_CONSTANTS、vasprun.xml进入Raman文件夹；获得对称性-获得特征标表或不可约表示的命令为：
   phonopy --dim="2 2 1" -c POSCAR-unitcell --readfc –irreps="0 0 0 1e-03"或
   phonopy --dim="2 2 1" -c POSCAR --readfc --ct="0 0 0 1e-03"

    phonopy --dim="3 3 3" -c POSCAR-unitcell --readfc –irreps="0 0 0 1e-03"

phonopy --dim="3 3 3" -c POSCAR-unitcell --readfc --irreps="0 0 0 1e-03"

 或建立包含上述参数的 irreps.conf文件，phonopy -p  irreps.conf >tmp即可得到包含特征标表的含振动频率的文件(输出到tmp)

cat irreps.conf

ATOM_NAME=H X
FORCE_CONSTANTS = READ
DIM=2 2 2
PRIMITIVE_AXIS = 0.0 0.5 0.5  0.5 0.0 0.5  0.5 0.5 0.0  【将常规晶胞转换为原胞primitive cell】
IRREPS = 0 0 0 1E-3  【0 0 0，Gama点的不可约表示？】
SHOW_IRREPS = .TRUE.
TOLERANCE = 1E-3

###加上ANIME_TYPE和ANIME这两个参数后，可在V_SIM软件中通过动画显示出，Raman谱峰对应的原子振动方式；选择Phonon，能量以THz单位表示

#ANIME_TYPE=V_SIM    

#ANIME=0.0 0.0 0.0

http://inac.cea.fr/L_Sim/V_Sim/

4. 或另建立band文件夹，编辑band.conf文件，使用命令得到声子谱色散曲线
    phonopy --dim="2 2 2" -c POSCAR-unitcell --readfc band.conf

   或phonopy -p --factor=521.471 band.conf  

5. 或另建立dos文件夹，编辑pdos.conf文件，使用命令得到声子态密度：

  phonopy -p --factor=521.471  pdos.conf

或pdosplot -i ’1 2 4 5, 3 6’ -o ’pdos.pdf’ partial_dos.dat

6. 或另建立zpe文件夹，编辑mesh.conf文件，使用命令得到零点振动能

  phonopy -t -p mesh.conf

或phonopy -t mesh.conf

bandplot --gnuplot band.yaml
pdosplot -i ’1 2 4 5, 3 6’ -o ’pdos.pdf’ partial_dos.dat
proplot thermal_properties_A.yaml thermal_properties_B.yaml

Notes:  

(1) xxxx.conf文件

cat   dos/pdos.conf

ATOM_NAME = H Sc

DIM = 2 2 1

FORCE_CONSTANTS = READ

MP = 8 8 8
GAMMA_CENTER = .TRUE.
PDOS = 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18, 19 20 21 22 23 24

cat   band/band.conf
ATOM_NAME = H Sc

DIM = 2 2 1

FORCE_CONSTANTS = READ

BAND=   0.000  0.000  0.000 0.000  0.000  0.500  -0.333  0.667  0.500 -0.333  0.667  0.000 0.000  0.000  0.000 0.000  0.500  0.000 0.000  0.500  0.500  -0.333  0.667  0.500

cat   zpe/mesh.conf
ATOM_NAME = H Sc

DIM = 2 2 1

FORCE_CONSTANTS = READ

MP = 8 8 8

GAMMA_CENTER = .TRUE.

TPROP = .TRUE.

(2) Plot操作

bandplot --gnuplot band.yaml
pdosplot -i ’1 2 4 5, 3 6’ -o ’pdos.pdf’ partial_dos.dat
proplot thermal_properties_A.yaml thermal_properties_B.yaml

Raman数据分析：

1）进入下述网站，分析特征标表， 分析哪些模式具有Raman

http://www.cryst.ehu.es/

http://www.cryst.ehu.es/cgi-bin/cryst/programs//nph-sam

2) phonopy --dim="2 2 1" -c POSCAR --readfc --irreps="0 0 0 1e-03" > ramanx.dat

检测ramanx.dat文件中的特标表，找到具有Raman活性的振动模式：

character_table.yaml  irreps.yaml  ramanx.dat

w = exp(2iπ/3)
( 0, 180.0)
（A,fai）
cos180+isin180

phase =eifai= cosfai+isinfai

Mannual

pdosplot

Partial density of states (PDOS) are plotted.

-i option is used as

The indices and comma in ‘1 2 3 4, 5 6’ mean as follows. The indices are separated into blocks by comma (1 2 4 5 and 3 6). PDOS specified by the successive indices separated by space in each block are summed up. The PDOS of blocks are drawn simultaneously. Indices usually correspond to atoms.  A few more options are prepared and shown by -h option.

问题：

1. 为何执行 后得不到不可约表示

phonopy --dim="2 2 1" -c POSCAR-unitcell --readfc --irreps="0 0 0 1e-03"
       _                                    
 _ __ | |__   ___  _ __   ___   _ __  _   _
| '_ | '_ / _ | '_ / _ | '_ | | | |
| |_) | | | | (_) | | | | (_) || |_) | |_| |
| .__/|_| |_|___/|_| |_|___(_) .__/ __, |
|_|                            |_|    |___/

                                    1.8.4

Ir-representation mode
Settings:
 Force constants: Read from FORCE_CONSTANTS
 Supercell:  [2 2 1]
Spacegroup:  P6_3 (173)

-----------------
Character table
-----------------
q-point: [ 0.  0.  0.]
Point group: 6

Original rotation matrices:

    1         2         3         4         5         6    
--------  --------  --------  --------  --------  --------
 1  0  0   0  1  0  -1  1  0  -1  0  0   0 -1  0   1 -1  0
 0  1  0  -1  1  0  -1  0  0   0 -1  0   1 -1  0   1  0  0
 0  0  1   0  0  1   0  0  1   0  0  1   0  0  1   0  0  1

Transformation matrix:

-1.000  1.000  0.000
-1.000  0.000  0.000
0.000  0.000  1.000

Rotation matrices by transformation matrix:

    1         2         3         4         5         6    
--------  --------  --------  --------  --------  --------
 1  0  0   0  1  0  -1  1  0  -1  0  0   0 -1  0   1 -1  0
 0  1  0  -1  1  0  -1  0  0   0 -1  0   1 -1  0   1  0  0
 0  0  1   0  0  1   0  0  1   0  0  1   0  0  1   0  0  1

Character table:

 1 (  -0.004):
   ( 2,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0)

 2 (  -0.003):
   ( 2,   0.0) ( 0,   0.0) ( 0, 180.0) ( 2, 180.0) ( 0, 180.0) ( 0,   0.0)

 4 (   4.445):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

 6 (   5.365):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

 7 (   6.315):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

 8 (   6.566):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

10 (   6.572):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

12 (   6.715):
   ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0)

13 (   8.099):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

15 (   8.177):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

17 (   8.283):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

18 (   8.491):
   ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0)

19 (  11.096):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

20 (  13.788):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

21 (  14.413):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

22 (  15.317):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

23 (  18.537):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

24 (  18.971):
   ( 2,   0.0) ( 0,   0.0) ( 0, 180.0) ( 2, 180.0) ( 0, 180.0) ( 0,   0.0)

26 (  19.279):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

28 (  19.788):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

29 (  21.523):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

30 (  21.611):
   ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0)

31 (  22.497):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

33 (  22.723):
   ( 1,   0.0) ( 0, 180.0) ( 0, 180.0) ( 1,   0.0) ( 0, 180.0) ( 0, 180.0)

35 (  23.960):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

36 (  25.345):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

37 (  27.380):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

38 (  27.689):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

40 (  28.524):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

42 (  29.938):
   ( 1,   0.0) ( 0, 180.0) ( 0,   0.0) ( 1, 180.0) ( 0,   0.0) ( 0, 180.0)

43 (  30.777):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

45 (  31.562):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

47 (  32.182):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

48 (  32.379):
   ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0)

49 (  32.743):
   ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0) ( 0,   0.0)

50 (  34.092):
   ( 2,   0.0) ( 0,   0.0) ( 0, 180.0) ( 2, 180.0) ( 0, 180.0) ( 0,   0.0)

52 (  34.340):
   ( 1,   0.0) ( 0, 180.0) ( 0, 180.0) ( 1,   0.0) ( 0, 180.0) ( 0, 180.0)

54 (  35.621):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

55 (  38.862):
   ( 2,   0.0) ( 0, 180.0) ( 0, 180.0) ( 2,   0.0) ( 0, 180.0) ( 0, 180.0)

57 (  38.937):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

59 (  39.623):
   ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0) ( 0,   0.0) ( 0, 180.0)

60 (  40.129):
   ( 1,   0.0) ( 0,   0.0) ( 0,   0.0) ( 1,   0.0) ( 0,   0.0) ( 0,   0.0)

61 (  40.728):
   ( 1,   0.0) ( 0, 180.0) ( 0, 180.0) ( 1,   0.0) ( 0, 180.0) ( 0, 180.0)

63 (  40.929):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

65 (  41.392):
   ( 1,   0.0) ( 0, 180.0) ( 0, 180.0) ( 1,   0.0) ( 0, 180.0) ( 0, 180.0)

67 (  41.555):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

69 (  43.031):
   ( 1,   0.0) ( 0,   0.0) ( 0, 180.0) ( 1, 180.0) ( 0, 180.0) ( 0,   0.0)

71 (  43.124):
   ( 2,   0.0) ( 1, 180.0) ( 1, 180.0) ( 2,   0.0) ( 1, 180.0) ( 1, 180.0)

                _
  ___ _ __   __| |
 / _ '_ / _` |
|  __/ | | | (_| |
 ___|_| |_|__,_|

网络摘录：

http://sourceforge.net/p/phonopy/mailman/message/31934387/

Phonopy can give you the character of the irreducible representation of each phonon mode. Use the IRREPS-tag. However symbols are not implemented for all point groups, but maybe you are lucky.

Then you can use bilbao crystallographic database (http://www.cryst.ehu.es/rep/sam.html) to see which of the modes are raman/IR active.

It is not possible to calculate the intensities with phonopy.

Hope that answers your question.

Cheers
Sebastian


Sebastian Christensen
PhD student
Center for Materials Crystallography
Department of Chemistry & iNANO, Aarhus University
Office: 1511-318
Langelandsgade 140, DK-8000 Aarhus C, Denmark
Mail:   sebastian@...

In the case of infrared and using Vasp, you can use

http://homepage.univie.ac.at/david.karhanek/downloads.html

while for Raman, you need the third order response (mix derivatives with
respect to
ionic positions and electric field, you can use Abinit or QE to get it…

Dear Carlo,

if you are using VASP, you can try vasp_raman.py script: https://github.com/raman-sc/VASP

Disclosure: I'm one of the contributors.


Best,
Alexandr,
Georgia tech.

http://sourceforge.net/p/phonopy/mailman/message/31624979/

Dear Saikat,

how do you get to the idea that Raman intensities are proportional to
the phonon DOS? It would be very interesting if there is some connection
between them.

As far as I know the Raman intensity is proportional to  
the change of the electrical polarisation caused by the lattice  
vibration of the phonon. (However it is better to look this up in  
literature) Thats why it is not calculated in phonopy.

Regards,
Torsten

Quoting saikat mukhopadhyay <saikatrel@...>:

> Dear  phonopy users,
>
> I was trying to  calculate Raman  intensities using  VASP-phonopy
> interface. I  got the  Raman and IR active modes  using "irreps" modules
> in  phonopy. However, I  could not   plot them as I am not  sure  how to
> assign the  heights  to the corresponding  Raman  active frequencies. One
> way to  do  that (I thought) would be to  grab the  PHDOS peaks
> corresponding to those active modes. But the problem is the  frequencies of
> the Raman active modes are  not the same as those  printed  in the
> total_dos.dat  files.
>
> Any  help would be  highly appreciated. I  welcome any  other  schemes  to
> calculate Raman  intensities from  PHDOS at Gamma.
>
> Thanks a lot.
>
> Sincerely,
> Saikat
>
>
> --
>
>
> *****silence is an art of conversation *****

Hi,

I don't know how to calculate Raman intensity.
IR intensity seems to be able to calculate a combination of techniques
implemented in VASP, but I've never tried yet.
http://homepage.univie.ac.at/david.karhanek/downloads.html

Togo