[Pw_forum] Orthogonality of wavefunctions

[Hua Bao]

Bo,

This is Hua Bao. I saw your post on pwforum. I tried to send a few emails
to the forum but they are not appear on the email list.
Do you need to do anything else to get it posted?


On Thu, Oct 31, 2013 at 10:11 PM, Bo Qiu <200210qb at gmail.com> wrote:

> Dear Paolo,
>
> Thanks for pointig that out! So if I use the real space representation of
> the periodic wavefunction (from cft_wave(evc)) with correct igk and later
> multiply them by exp（ikr）and integrate in a real space volume, they should
> give me the orthogonality for different k k'?
>
> Thanks a lot,
> Bo
> On Oct 31, 2013 6:07 AM, "Paolo Giannozzi" <paolo.giannozzi at uniud.it>
> wrote:
>
>> Bloch states at different k are orthogonal because they have different
>> k, not because their periodic parts are orthogonal, so your test is not
>> a valid one. Note that you have to take into account the different
>> ordering of plane waves (array igk) at k and k' when computing
>> <k| something |k'>
>>
>> P.
>>
>> On Thu, 2013-10-31 at 02:13 -0400, Bo Qiu wrote:
>> > Dear developers and users,
>> >
>> >
>> > I'm trying to compute some matrix elements between states k and k'. To
>> > confirm my calculation, I first try to compute the overlap between
>> > wavefunction k and k' as  < k| k'> in quantum espresso by taking zdoc
>> > of state k and k' (modified the elphonon.f90 code). I do find for the
>> > same k point, the overlap between different bands are 0. However, the
>> > overlap between two states at different points k and k' are almost
>> > always non-zero, indicating they're not orthogonal. I thought in
>> > theory they should all be orthonormal because they belong to the same
>> > Hamiltonian of the entire system. So is it because of numerical
>> > reasons that they're actually not orthogonal in quantum espresso?
>> >
>> >
>> > Thanks a lot for you help!
>> >
>> >
>> > Bo
>> > _______________________________________________
>> > Pw_forum mailing list
>> > Pw_forum at pwscf.org
>> > http://pwscf.org/mailman/listinfo/pw_forum
>>
>> --
>>  Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
>>  Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>>  Phone +39-0432-558216, fax +39-0432-558222
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20131103/014cb3dc/attachment.html>