Bilbao Crystallographic Server IR Raman Hyper-Raman Modes

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Information of the Point Group C_3i (-3)

Character Table¹

C3i(-3)	#	1	3+	3-	-1	-3+	-3-	functions
Ag	Γ1+	1	1	1	1	1	1	x2+y2,z2,Jz
1Eg 2Eg	Γ3+ Γ2+	1 1	w2 w	w w2	1 1	w2 w	w w2	(xz,yz),(x2-y2,xy),(Jx,Jy)
Au	Γ1-	1	1	1	-1	-1	-1	z
1Eu 2Eu	Γ3- Γ2-	1 1	w2 w	w w2	-1 -1	-w2 -w	-w -w2	(x,y)


w = exp(2iπ/3)

To get the list of the irreducible representations in their matrix form please click here.



Raman and Hyper-Raman Tensors

Raman Tensors	Hyper-Raman Tensors
Ag 1Eg 2Eg a · · c d e d -c -f · a · d -c f -c -d e · · b e f · -f e ·	Au(z) 1Eu(x) 2Eu(y) a -a · · c -b 3e e g · -f h -3h -h -i k -j e -b b · c · -a h 3h i f · e e 3e g j k -h c c d · · · -f f · i g · -j j · g -i k


To transform the tensors please click here.

Information of the Space Group P-3 (No. 147)

Selection Rules

In the following tables one can find which are the allowed representations for each one of the selected Wyckoff positions for IR, Raman and Hyper-Raman processes.


• IR Active Modes: (Γ_acoustic = A_u + ¹E_u + ²E_u )



WP	Ag	Au	1Eg	1Eu	2Eg	2Eu
3e	·	3	·	3	·	3




• Raman Active Modes



WP	Ag	Au	1Eg	1Eu	2Eg	2Eu
3e	·	·	·	·	·	·




• Hyper-Raman Active Modes



WP	Ag	Au	1Eg	1Eu	2Eg	2Eu
3e	·	3	·	3	·	3



The polarization selection rules for Raman and Hyper-Raman processes.



Modes Activity

This table is a summary of the activity of the different modes of the space group.



-	Ag	Au	1Eg	1Eu	2Eg	2Eu
Infrared	·	x	·	x	·	x
Raman	x	·	x	·	x	·
Hyper-Raman	·	x	·	x	·	x

Note: x ≡ represents the modes which can be detected.


More information:



Permutational Representation

The permutational representation represents the number of atoms that are invariant under the symmetry operations of the group. In this table one can find the representation for each one of the Wyckoff positions.



WP	Ag	Au	1Eg	1Eu	2Eg	2Eu
3e	1	·	1	·	1	·




Mechanical Representation

The mechanical representation is defined as the direct product of the permutational representation with the vectorial representation. The mechanical representation for each one of the chosen Wyckoff positions is given in the following table.



WP	Ag	Au	1Eg	1Eu	2Eg	2Eu	Modes
3e	·	3	·	3	·	3	Show

Note: Click in the Show option to obtain the symmetry adapted modes for a given orbit.


Irreps decompositions

In the following table one can find the decomposition of the vectorial, pseudo vectorial and so on representations.



C3i (-3)	Ag	Au	1Eg	1Eu	2Eg	2Eu
V	·	1	·	1	·	1
A	1	·	1	·	1	·
[V2]	2	·	2	·	2	·
[V2] x V	·	6	·	6	·	6

Information about second order processes:



Second Order IR Activity

In the next table one can find the information the second order IR active modes:



⊗ Ag Au 1Eg 1Eu 2Eg 2Eu Ag Ag Au 1Eg 1Eu 2Eg 2Eu Au · Ag 1Eu 1Eg 2Eu 2Eg 1Eg · · 2Eg 2Eu Ag Au 1Eu · · · 2Eg Au Ag 2Eg · · · · 1Eg 1Eu 2Eu · · · · · 1Eg

Active               Inactive       bold   IR active modes





Second Order Raman Activity

In the next table one can find the information the second order Raman active modes:



⊗ Ag Au 1Eg 1Eu 2Eg 2Eu Ag Ag Au 1Eg 1Eu 2Eg 2Eu Au · Ag 1Eu 1Eg 2Eu 2Eg 1Eg · · 2Eg 2Eu Ag Au 1Eu · · · 2Eg Au Ag 2Eg · · · · 1Eg 1Eu 2Eu · · · · · 1Eg

Active               Inactive       bold   Raman active modes


For more information about the second order Raman go the the program RAMAN