### diople calculation

Posted:

**Sat Nov 24, 2018 5:01 pm**Hi all,

I have a stupid question here.

I want to calculate dielectric function within RPA (-o c).

I notice that, for q1 (0,0,0), dipoles P and iR will be calculated first:

<20s> P0001: [WF] Performing Wave-Functions I/O from ./SAVE

<22s> P0001: Dipoles: P and iR (T): | | [000%] --(E) --(X)

<33s> P0001: Dipoles: P and iR (T): |# | [002%] 10s(E) 07m-13s(X)

and then enter response function calculation:

<07m-39s> P0001: Xo@q[1] | | [000%] --(E) --(X)

<07m-44s> P0001: Xo@q[1] |#################### | [052%] 05s(E) 09s(X)

<07m-48s> P0001: Xo@q[1] |########################################| [100%] 09s(E) 09s(X)

but for finite q, response function would be calculated directly after reading wavefunction from ./SAVE while dipoles are not calculated.

<21s> P0001: [WF] Performing Wave-Functions I/O from ./SAVE

<21s> P0001: [FFT-X] Mesh size: 21 21 48

<39s> P0001: [X-CG] R(p) Tot o/o(of R) : 51399 258176 100

<39s> P0001: [X] Upper matrix triangle filled

<39s> P0001: Xo@q[6] | | [000%] --(E) --(X)

<44s> P0001: Xo@q[6] |# | [004%] 05s(E) 01m-48s(X)

Q: why is dipole calculation only necessary for q1 vector? what is the difference between q=0 and finite q calculation ?

I have a stupid question here.

I want to calculate dielectric function within RPA (-o c).

I notice that, for q1 (0,0,0), dipoles P and iR will be calculated first:

<20s> P0001: [WF] Performing Wave-Functions I/O from ./SAVE

<22s> P0001: Dipoles: P and iR (T): | | [000%] --(E) --(X)

<33s> P0001: Dipoles: P and iR (T): |# | [002%] 10s(E) 07m-13s(X)

and then enter response function calculation:

<07m-39s> P0001: Xo@q[1] | | [000%] --(E) --(X)

<07m-44s> P0001: Xo@q[1] |#################### | [052%] 05s(E) 09s(X)

<07m-48s> P0001: Xo@q[1] |########################################| [100%] 09s(E) 09s(X)

but for finite q, response function would be calculated directly after reading wavefunction from ./SAVE while dipoles are not calculated.

<21s> P0001: [WF] Performing Wave-Functions I/O from ./SAVE

<21s> P0001: [FFT-X] Mesh size: 21 21 48

<39s> P0001: [X-CG] R(p) Tot o/o(of R) : 51399 258176 100

<39s> P0001: [X] Upper matrix triangle filled

<39s> P0001: Xo@q[6] | | [000%] --(E) --(X)

<44s> P0001: Xo@q[6] |# | [004%] 05s(E) 01m-48s(X)

Q: why is dipole calculation only necessary for q1 vector? what is the difference between q=0 and finite q calculation ?