[CP2K-user] [CP2K:10343] transition dipole moment

[Xiaoming Wang]

Hi Nuri,
Thanks for your clarification.

Best,
Xiaoming

On Friday, October 12, 2018 at 7:47:40 AM UTC-4, Nuri Yazdani wrote:
>
> Hi Xiaoming,
> You are right, the MOs are not normalised. However, and I am not 100% sure 
> about this, I think that they shouldnt necessarily be normalized, since the 
> basis functions (i.e. the gaussian orbital on each atom) are not orthogonal 
> to one another. This is where the overlap matrix comes in..  
> So, I think, if one wants to construct for example the electron density 
> from the MOs and the basis functions, one should use the MO coefficients as 
> is (i.e. do not renormalise the MOs yourself). 
> I think, and again I am not totally confident about this, that if you 
> print out the overlap matrix S, you can get the dipole moment (missing some 
> prefactors, and for example the x component) by
>
> A_ij,x = <mo_i| S x |mo_j>
>
> The problem that I have is that I have already run really large MD 
> calculations, and I only was printing out the MOs. I think the best I can 
> do then is to use
>
> A_ij,x ~ <mo_i| x |mo_j>
>
> which from my understanding, ignores any contribution to A_ij,x from 
> orbitals on two different atoms. For my system, A_ij,x will be dominated by 
> s -> p transitions on one particular atomic species, so this approximation 
> should be OK, but it may fail terribly for systems where the transition 
> goes from an orbital on one atom type to an orbital on a different atom 
> type..
>
> On Wednesday, October 10, 2018 at 2:49:34 PM UTC+2, Xiaoming Wang wrote:
>>
>> Hi Nuri,
>>
>> Are you using the MOS? The mo coefficients are not normalized, how do you 
>> solve this problem?
>>
>> Best,
>> Xiaoming
>>
>> On Tuesday, October 9, 2018 at 7:31:19 AM UTC-4, Nuri Yazdani wrote:
>>>
>>> Hi Prof. Hutter,
>>>
>>> I am trying to do such calculations. I have printed out the MOS from my 
>>> calculations to do this, however, I am quite confused by the spatial 
>>> representation and ordering of the d-orbitals... 
>>>
>>> I am using the MOLOPT-DZVP basis set. For example, for Cs 
>>> DZVP-MOLOPT-SR-GTH 1 2 0 2 6 3 2 1, I have 3x S, 6x P, and 5x D orbitals 
>>> (this counting is also consistent with the length of my MOSs).
>>>
>>> The S and P orbitals I can construct from the basis set, and (if CGS are 
>>> a linear combination of gaussians) the p orbitals are px = x*CGS, py = 
>>> y*CGS, pz =z*CGS, however, what is the ordering and form of the d 
>>> orbitals?? i.e. what is r^2 equal to in each of the 5 last lines of this 
>>> page: https://www.cp2k.org/basis_sets? 
>>>
>>> Cheers,
>>> Nuri
>>>
>>>
>>>
>>>
>>> On Thursday, May 31, 2018 at 11:28:04 AM UTC+2, jgh wrote:
>>>>
>>>> Hi 
>>>>
>>>> this property is on our TO DO list. However, I cannot say when 
>>>> it will become available. 
>>>>
>>>> If you want to calculate it yourself from the MO cube files 
>>>> you need to use the Berry phase algorithm, meaning you need 
>>>>
>>>> mu = IMAG LOG <phi_a | exp(i*k*r) |phi_b> 
>>>>
>>>> However, this can be calculated much more efficiently from 
>>>> the atomic basis functions. 
>>>>
>>>> regards 
>>>>
>>>> Juerg Hutter 
>>>> -------------------------------------------------------------- 
>>>> Juerg Hutter                         Phone : ++41 44 635 4491 
>>>> Institut für Chemie C                FAX   : ++41 44 635 6838 
>>>> Universität Zürich                   E-mail: hut... at chem.uzh.ch 
>>>> Winterthurerstrasse 190 
>>>> CH-8057 Zürich, Switzerland 
>>>> --------------------------------------------------------------- 
>>>>
>>>> -----cp... at googlegroups.com wrote: ----- 
>>>> To: cp2k <cp... at googlegroups.com> 
>>>> From: Xiaoming Wang 
>>>> Sent by: cp... at googlegroups.com 
>>>> Date: 05/24/2018 05:07PM 
>>>> Subject: [CP2K:10343] transition dipole moment 
>>>>
>>>> Hi, 
>>>>
>>>> Is it possible for CP2K to output the transition dipole moment <phi_A | 
>>>> r | phi_B>  between two KS states, say HOMO to LUMO transition? 
>>>> I tried to calculate the integral by printing the MO_CUBE files which 
>>>> are the phi_A and phi_B and then do the integration. This is fine for 
>>>> molecules or in other word non-periodic systems. But for periodic 
>>>> systems, the result was not as expected, maybe due to the position 
>>>> operator is ill-defined in that case. So how to evaluate the transition 
>>>> dipole integral for periodic systems with the MO_CUBE files known? 
>>>>
>>>> Best, 
>>>> Xiaoming     
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>>>>
>>>
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