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再谈Raman光谱
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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+6B1g+3B2g+3B3g),
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
| SAM | Spectral Active Modes (IR, RAMAN and HYPER-RAMAN Selection Rules) |
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
https://blog.sciencenet.cn/blog-567091-843365.html
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