[CPMD-list] Si(001)-(1x2)

[Mehmet Cakmak]

Dear All,

Some reason I cannot get the right tilt angle and the bond 
length for dimer at the Si(001)-(1x2) surface. Please take a 
look my input file and let me know If I do something wrong.
thank you
	-mehmet


&CPMD
OPTIMIZE GEOMETRY
CONJUGATE GRADIENTS ELECTRONS,IONS
STRUCTURE BONDS ANGLES DIHEDRAS 
SPLINE QFUNCTIONS POINTS 
6000
BIG MEMORY
CONVERGENCE
1.0E-2 1.0E-3
&END
&SYSTEM
SYMMETRY
     8
SURFACE
  CELL ABSOLUTE
7.2448859214782715  14.4897718429565430  62.7556228637695312  0  0  0
CUTOFF
36. 
POISSON SOLVER MORTENSEN
SURFACE
&END
&ATOMS
  CONSTRAINTS
    FIX COORDINATES
        4
        1  0 0 0
        2  0 0 0
        3  0 0 0
        4  0 0 0
  END CONSTRAINTS
*Si_SG_LDA
  LMAX=P
   24
   0.0000000000000000   0.0000000000000000   0.0000000000000000      1
   0.0000000000000000   7.2448859214782715   0.0000000000000000      1
   3.6224429607391357   0.0000000000000000   2.5614535808563232      1
   3.6224429607391357   7.2448859214782715   2.5614535808563232      1
   3.6224429607391357   3.6224429607391357   5.1229071617126465      1
   3.6224429607391357  10.8673286437988281   5.1229071617126465      1
   0.0000000000000000   3.6224429607391357   7.6843624114990234      1
   0.0000000000000000  10.8673286437988281   7.6843624114990234      1
   0.0000000000000000   0.0000000000000000  10.2458162307739258      1
   0.0000000000000000   7.2448859214782715  10.2458162307739258      1
   3.6224429607391357   0.0000000000000000  12.8072700500488281      1
   3.6224429607391357   7.2448859214782715  12.8072700500488281      1
   3.6224429607391357   3.6224429607391357  15.3687248229980469      1
   3.6224429607391357  10.8673286437988281  15.3687248229980469      1
   0.0000000000000000   3.6224429607391357  17.9301776885986328      1
   0.0000000000000000  10.8673286437988281  17.9301776885986328      1
   0.0000000000000000   0.0000000000000000  20.1714477539062500      1
   0.0000000000000000   7.2448859214782715  20.1714477539062500      1
   3.6224429607391357   0.0000000000000000  22.6432533264160156      1
   3.6224429607391357   7.2448859214782715  22.6432533264160156      1
   3.6224429607391357   3.6224429607391357  25.4096240997314453      1
   3.6224429607391357  10.8673286437988281  25.4096240997314453      1
   0.0000000000000000   5.2163181304931641  28.2000000000000000      1
   0.0000000000000000   9.2734537124633789  27.9786328125000000      1
*H_SG_LDA
   LMAX=P
   4
   0.0000000000000000   2.1734659671783447  -2.1964468955993652      1
   0.0000000000000000   5.0714201927185059  -2.1964468955993652      1
   0.0000000000000000   9.4183511734008789  -2.1964468955993652      1
   0.0000000000000000  12.3163070678710938  -2.1964468955993652      1
&END