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hanyanli0475

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[求助] 建模面心正交晶格体心四方晶格

各位高手大家好，我今天看了一篇文献，讲镓有很多种结构，其中属（a-Ga）面心正交晶格总能最稳定。我现在想用MS建模，可以没有找到Ga的相关结构，请问在MS中哪一种化合物的晶格结构是面心正交晶格呢？？
还有哪一种化合物属于体心四方晶格呢？？
急求帮助，各位高手帮帮忙哦！！

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1楼 2012-01-06 14:49:13

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dxcharlary

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★
感谢参与，应助指数 +1
liliangfang(金币+1): 多谢提示 2012-01-06 19:52:19

一般文献中或者其参考文献中都会有晶体的对称性群，a，b，c长度，还有原子的位置，楼主再仔细看看文献。

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2楼2012-01-06 19:49:53

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hanyanli0475

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各位高手能再给点意见吗？我找了两天也没找到a-Ga）面心正交晶格的原子坐标，现在卡在这了，有点着急了。谢谢！

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3楼2012-01-08 21:02:41

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frank_zhan

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fzx2008: 金币+2, 谢谢指教 2012-06-21 14:26:23

ibrav is the structure index:

ibrav       structure                celldm(2)-celldm(6)

   0       "free", see above                not used
   1       cubic P (sc)                   not used
   2       cubic F (fcc)                   not used
   3       cubic I (bcc)                   not used
   4       Hexagonal and Trigonal P       celldm(3)=c/a
   5       Trigonal R                   celldm(4)=cos(alpha)
   6       Tetragonal P (st)             celldm(3)=c/a
   7       Tetragonal I (bct)             celldm(3)=c/a
   8       Orthorhombic P                celldm(2)=b/a,celldm(3)=c/a
   9       Orthorhombic base-centered(bco) celldm(2)=b/a,celldm(3)=c/a
   10       Orthorhombic face-centered    celldm(2)=b/a,celldm(3)=c/a
   11       Orthorhombic body-centered    celldm(2)=b/a,celldm(3)=c/a
   12       Monoclinic P                   celldm(2)=b/a,celldm(3)=c/a,
                                             celldm(4)=cos(ab)
   13       Monoclinic base-centered       celldm(2)=b/a,celldm(3)=c/a,
                                             celldm(4)=cos(ab)
   14       Triclinic                      celldm(2)= b/a,
                                             celldm(3)= c/a,
                                             celldm(4)= cos(bc),
                                             celldm(5)= cos(ac),
                                             celldm(6)= cos(ab)

  For P lattices: the special axis (c) is the z-axis, one basal-plane
  vector (a) is along x, the other basal-plane vector (b) is at angle
  gamma for monoclinic, at 120 degrees for trigonal and hexagonal
  lattices, at 90 degrees for cubic, tetragonal, orthorhombic lattices

  sc simple cubic
  ====================
  a1 = a(1,0,0),  a2 = a(0,1,0),  a3 = a(0,0,1)

  fcc face centered cubic
  ====================
  a1 = (a/2)(-1,0,1),  a2 = (a/2)(0,1,1), a3 = (a/2)(-1,1,0).

  bcc body entered cubic
  ====================
  a1 = (a/2)(1,1,1),  a2 = (a/2)(-1,1,1),  a3 = (a/2)(-1,-1,1).

  simple hexagonal and trigonal(p)
  ====================
  a1 = a(1,0,0),  a2 = a(-1/2,sqrt(3)/2,0),  a3 = a(0,0,c/a).

  trigonal(r)
  ===================
  for these groups, the z-axis is chosen as the 3-fold axis, but the
  crystallographic vectors form a three-fold star around the z-axis,
  and the primitive cell is a simple rhombohedron. The crystallographic
  vectors are:
      a1 = a(tx,-ty,tz), a2 = a(0,2ty,tz), a3 = a(-tx,-ty,tz).
  where c=cos(alpha) is the cosine of the angle alpha between any pair
  of crystallographic vectors, tc, ty, tz are defined as
   tx=sqrt((1-c)/2), ty=sqrt((1-c)/6), tz=sqrt((1+2c)/3)

  simple tetragonal (p)
  ====================
   a1 = a(1,0,0),  a2 = a(0,1,0),  a3 = a(0,0,c/a)

  body centered tetragonal (i)
  ================================
   a1 = (a/2)(1,-1,c/a),  a2 = (a/2)(1,1,c/a),  a3 = (a/2)(-1,-1,c/a).

  simple orthorhombic (p)
  =============================
   a1 = (a,0,0),  a2 = (0,b,0), a3 = (0,0,c)

  bco base centered orthorhombic
  =============================
   a1 = (a/2,b/2,0),  a2 = (-a/2,b/2,0),  a3 = (0,0,c)

  face centered orthorhombic
  =============================
   a1 = (a/2,0,c/2),  a2 = (a/2,b/2,0),  a3 = (0,b/2,c/2)

  body centered orthorhombic
  =============================
   a1 = (a/2,b/2,c/2),  a2 = (-a/2,b/2,c/2),  a3 = (-a/2,-b/2,c/2)

  monoclinic (p)
  =============================
   a1 = (a,0,0), a2= (b*sin(gamma), b*cos(gamma), 0),  a3 = (0, 0, c)
  where gamma is the angle between axis a and b

  base centered monoclinic
  =============================
   a1 = (  a/2,       0,             -c/2),
   a2 = (b*cos(gamma), b*sin(gamma), 0),
   a3 = (  a/2,       0,                c/2),
  where gamma is the angle between axis a and b

  triclinic
  =============================
   a1 = (a, 0, 0),
   a2 = (b*cos(gamma), b*sin(gamma), 0)
   a3 = (c*cos(beta),  c*(cos(alpha)-cos(beta)cos(gamma))/sin(gamma),
         c*sqrt( 1 + 2*cos(alpha)cos(beta)cos(gamma)
                  - cos(alpha)^2-cos(beta)^2-cos(gamma)^2 )/sin(gamma) )
  where alpha is the angle between axis b and c
      beta is the angle between axis a and c
      gamm  is the angle between axis a and b

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4楼2012-06-21 11:23:11

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