[Pw_forum] monoclinic structure with unique c axis

[sathya subramanyan]

Dear All,
          I'm trying to optimize a monoclinic structure(C2/c). I have the experimental atomic postions(wycoff)with b axis as unique.I think in espresso the monoclinic structure positions have to be given taking c axis as unique.
        My question is can the y axis value(b axis unique) of 4e wycoff site be taken as the z axis value of 4e site (with unique axis c).I have put the wycoff postions both with c and b a=xis unique for C2/c structure. Please do help me out.Thank You in advance

Wyckoff Positions of Group 15 (C2/c) [unique axis c]
Multiplicity           Coordinates
8 f 1           (x,y,z)  (-x+1/2,-y,z)  (-x,-y,-z)  (x+1/2,y,-z)  
 
4 e 2           (1/4,0,z)  (3/4,0,-z)  
 
4 d -1          (1/2,1/4,1/4)  (0,3/4,1/4)  
 
4 c -1          (0,1/4,1/4)  (1/2,3/4,1/4)  
 
4 b -1          (0,0,1/2)  (1/2,0,1/2)  
 
4 a -1          (0,0,0)  (1/2,0,0)  

 Wyckoff Positions of Group 15 (C2/c) [unique axis b]
Multiplicity                     Coordinates 
8 f 1               (x,y,z)  (-x,y,-z+1/2)  (-x,-y,-z)  (x,-y,z+1/2)  
 
4 e 2               (0,y,1/4)  (0,-y,3/4)  
 
4 d -1              (1/4,1/4,1/2)  (3/4,1/4,0)  
 
4 c -1              (1/4,1/4,0)  (3/4,1/4,1/2)  
 
4 b -1              (0,1/2,0)  (0,1/2,1/2)  
 
4 a -1              (0,0,0)  (0,0,1/2)  
 

Regards




SATHYA SHEELA.S
Grad. Student
Department of Physics 
National Institute of Technology
Tiruchirapalli - 620015 
India
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