关注：

 1) k点和q点的物理意义；

 2) k点和q点在倒空间的取样方法；

 3) 电声耦合作用计算时，k点和q点的取点要求

1.nq,xq的区别

nq属于放入这个&INPUTPH字段中的参数

事例：

（1）

phonon of a225  at  Gamma

&inputph

tr2_ph=1.0d-12,

prefix='a225',

amass(1)=1.008

amass(2)=44.955910,

trans=.true.,

ldisp=.true.,

outdir='/home/xiaoqiugood/pwscf/pw/tmp/tmp3',

fildyn='a225.dyn',

nq1=4,nq2=4,nq3=4

/

（2）

cat > phdos.in <<EOF

&input

   asr='simple',

   dos=.true.,

   amass(1)=1.008,

   amass(2)=44.955910,

   flfrc='a225.fc',

   nk1=20,nk2=10,nk3=10,

   deltaE=1.0,

   fldos='a225.dos'

/

EOF

$PW_ROOT/matdyn.x < phdos.in > phdos.out

（3）

cat > q2r.in << EOF

&input

  fildyn='a225.dyn', zasr='simple', flfrc='a225.fc'

/

EOF

$PW_ROOT/q2r.x < q2r.in > q2r.out

cat > matdyn.in << EOF

&input

   asr='simple',  amass(1)=1.008, amass(2)=44.955910

   flfrc='a225.fc', flfrq='a225.freq'

/

151

 -1.000000      0.5000000      0.0000000E+00           1

-0.9833333      0.5000000      1.6666669E-02           2

-0.9666667      0.5000000      3.3333331E-02           3

-0.9500000      0.5000000      5.0000001E-02           4

....

-0.7500000      0.7500000      0.0000000E+00         151

EOF

$PW_ROOT/matdyn.x < matdyn.in > matdyn.out

(4)

ic=6

qpoints="0.500000000000000E+00,-0.500000000000000E+00,0.100000000000000E+01\

 -0.250000000000000E+00,-0.125000000000000E+01,0.250000000000000E+00\

 -0.500000000000000E+00,-0.500000000000000E+00,0.000000000000000E+00\

  0.000000000000000E+00,-0.100000000000000E+01,0.500000000000000E+00\

  0.500000000000000E+00,-0.500000000000000E+00,-0.500000000000000E+00"

for qpoint in $qpoints ; do

ic=`expr $ic + 1`

qx=`echo $qpoint | cut -d, -f1`

qy=`echo $qpoint | cut -d, -f2`

qz=`echo $qpoint | cut -d, -f3`

cat >$name.ph$ic.in << EOF

phonon of $name  at  Gamma

&inputph

tr2_ph=1.0d-12,

prefix='$name',

amass(1)=1.008

amass(2)=44.955910,

outdir='$TMP_DIR',

fildyn='$name.dyn$ic',

/

$qx $qy $qz

EOF

$PARA_PREFIX  $PW_ROOT/ph.x  < $name.ph$ic.in > $name.ph$ic.out

done

2. 对称性问题