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标题: 声子振动频率（LO与TO） [打印本页]

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Author: didi_dudu 时间: 2015-7-17 09:20
标题: 声子振动频率（LO与TO）
file:///C:\Users\002\AppData\Roaming\Tencent\Users\404227815\QQ\WinTemp\RichOle\SGVN(K@1UD2$_4H2TC_1CIJ.png (, 下载次数 Times of downloads: 40)
quantum espresso可以比较轻松的计算high frequency dielectric constant。然而直接计算static diele就不行了。我查到有文献说可以用上图的方法来求出static diele。然后我尝试着算了一下声子，得到这一堆关于频率的输出文件。我想请问下这些指的是什么呢？其中哪个数据指LO,哪个指TO呢？
   q = ( 0.000000000 0.000000000 0.000000000 )

**************************************************************************
   freq ( 1) =    -1.075131 [THz] =    -35.862513 [cm-1]
   freq ( 2) =    -1.075131 [THz] =    -35.862513 [cm-1]
   freq ( 3) =    -0.144628 [THz] =    -4.824280 [cm-1]
   freq ( 4) =    7.084979 [THz] =    236.329459 [cm-1]
   freq ( 5) =    7.084979 [THz] =    236.329459 [cm-1]
   freq ( 6) =    16.245046 [THz] =    541.876405 [cm-1]
   freq ( 7) =    18.266027 [THz] =    609.289063 [cm-1]
   freq ( 8) =    19.690865 [THz] =    656.816560 [cm-1]
   freq ( 9) =    19.690865 [THz] =    656.816560 [cm-1]
   freq ( 10) =    19.904301 [THz] =    663.936011 [cm-1]
   freq ( 11) =    19.904301 [THz] =    663.936011 [cm-1]
   freq ( 12) =    21.444431 [THz] =    715.309236 [cm-1]
**************************************************************************

   Mode symmetry, C_3v (3m) point group:

   freq (  1 -  2) =       -35.9  [cm-1] --> E L_3       I+R
   freq (  3 -  3) =       -4.8  [cm-1] --> A_1  L_1       I+R
   freq (  4 -  5) =       236.3  [cm-1] --> E L_3       I+R
   freq (  6 -  6) =       541.9  [cm-1] --> A_1  L_1       I+R
   freq (  7 -  7) =       609.3  [cm-1] --> A_1  L_1       I+R
   freq (  8 -  9) =       656.8  [cm-1] --> E L_3       I+R
   freq ( 10 - 11) =       663.9  [cm-1] --> E L_3       I+R
   freq ( 12 - 12) =       715.3  [cm-1] --> A_1  L_1       I+R
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