## Calculating spin-orbit matrix elements

(It is not necessary to upload input files, they can be found in the output file.)

qinghua
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### Re: Calculating spin-orbit matrix elements

Dear Olav,

Thank you for your reply! But in some literature they used the S1 or T1 optimized geometry to calculated SOC. It's there any distinctions?

Best regards!

Qinghua

taylor
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### Re: Calculating spin-orbit matrix elements

It is difficult to understand what you are asking. Obviously, if you run calculations at different geometries you will obtain different results for any property. Whether they will change much depends on the system and the property of interest. As an extreme example, you can calculate the dipole moment of HF, which near the minimum in the potential will be substantial. If you dissociate the molecule (with a wave function, such as MCSCF, that can describe this qualitatively correctly) you will obtain an H atom and an F atom and the dipole moment will be zero. (Actually, as a result of symmetry-breaking in the asymptotic limit this is not exactly true, but it is close enough.)

So what is it you want to calculate, and why? And what (say) experiments are you trying to compare with. I have lost count, if not yet patience, of my postings pleading with people to tell us what it is they are actually trying to calculate! As opposed to "some people do it this way, some people do it that way, what should I do"?!

Best regards
Pete

qinghua
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### Re: Calculating spin-orbit matrix elements

Dear Pete,
Sorry to make you confuse. I am want to computing SOCs between higher-lying singlet and triplet excited states. But in some literature, for example(Dyes and Pigments, 2016, 130, 9 and J. Org. Chem. 2015, 80, 5958−5963), they respectively using the S1 and T1 optimized geometry. This is what I feel confused.
Thank you very much and best regards!
Qinghua

taylor
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### Re: Calculating spin-orbit matrix elements

So if you use Dalton to calculate these sorts of properties you will run one calculation at a specific geometry. With such methodology it is not possible to calculate properties where e.g. S1 is at some calculated equilibrium geometry and T1 is at some different calculated equilibrium geometry. You need to ask yourself what is relevant for what you want to study. For example, if the ultimate interest were relaxation via phosphorescence to the ground state, most likely you would want to use the ground-state geometry. If your interest is relaxation of excited singlets to the lowest excited triplet (and no further) you might want to use excited-state geometries. There is no "one-size" answer here --- it depends, as I said in my previous posting, what it is you wish to compute. If I may editorialize further, it is not always wise to look at what previous authors have done. Much more important is to understand what (e.g.) experimentalists are doing, and what they need to help explain/interpret their experiments. But do not rely on experimentalists to tell you what they (think they) need to know! All too often experimentalists will say they need to know "this" because they do not believe, or are unaware, that we can calculate "that", which is what they really need. Understand their experiment, and if you can relate it properties that can be calculated, do those calculations.

Best regards
Pete

qinghua
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### Re: Calculating spin-orbit matrix elements

Dear Pete,
Many thanks to you for your help!
Thanks again and best regards!
Qinghua

xiaolin wang
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### Re: Calculating spin-orbit matrix elements

Dear everyone:
I want to know how to calculate spin-orbit coupling matrix element between ground state and triplet state.Where should I set it up？Which parameters should be changed?（I have carefully read input that calculates SOC between the single excited states and the triplet state ）

hjaaj
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### Re: Calculating spin-orbit matrix elements

For Breit-Pauli spin-orbit coupling (both one- and two-electron operators) between singlet ground state and triplet excited states at the MCSCF level, see the test `rsp_sreslrso`.

For AMFI mean-field spin-orbit coupling, change the input keyword `.SPIN-O` to `.MNF-SO`.

-- Hans Jørgen.

xiaolin wang
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### Re: Calculating spin-orbit matrix elements

Dear hjaaj
Thank you fou your help. I, a tyro, calculate phosphorescent materials containing heay atoms(Iridium or Platinum). I have computed the example you recommended. But I do not know where the soc matrix element between ground state and triplet state of output is. Meanwhile, I have calculated one file about heay atom Iridium, but it can not end normally. I hope to get your help.(s-t_s-t4.out is recommended example, and s0-t1_peng-1.out is my molecule.)

Thanks and best wishes !
Attachments
s0-t1_peng-1.out
s-t_s-t4.out

taylor
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### Re: Calculating spin-orbit matrix elements

If you are interested in "phosphorescence" (by which I mean decay back to the ground state from a triplet state after intersystem crossing from a singlet state), Dalton can calculate this directly: this is documented in the manual. I am not sure why you want to calculate some spin-orbit matrix elements directly?

Note that if you are calculating heavy elements and are using ECPs (it is not right now convenient for me to download your outputs so I cannot see them: that is a function of my situation and not in any way your fault!) you must, I am pretty sure, avoid the mean-field (AMFI) approach. If I recall correctly, Bernd Schimmelpfennig, who is expert in this area, has posted on this before. AMFI and ECPs are not designed to co-exist, I think.

Best regards
Pete

xiaolin wang
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### Re: Calculating spin-orbit matrix elements

Dear Pete,
Thank you very much for your reply. I need to discuss two aspects of radiative and non-radiative transitions about Phosphorescent organic metal complexes. I want to discuss the elements ,such as transition dipole moment and matrix element, which influences radiative transition rate. I use the effective-core one-electron spin-orbit operator method with ECP basis set to compute SOC matrix element between singlet excited states and triplet states, am I correct? If I am wrong, please correct me. Meanwhile, I need to discuss non-radiative transition that is affected by matrix element between ground state and lowest triplet state. So, I would like to calculate matrix element between ground state and lowest triplet state. I read the previous post and the output, but I do not know how to define SOC matrix element between the ground state and the triplet state. In recommended example that I test, I do not find where I want the data is. I need your help.

Thanks again and best regards!
xiaolin

taylor
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### Re: Calculating spin-orbit matrix elements

I am not an expert in these sorts of calculations, but I am pretty sure, based on previous postings, more expert people like Bernd Schimmelpfennig or Olav Vahtras would say that it is not reasonable to use an effective spin-orbit method like AMFI with conventional ECPs. Because the latter were parametrized without any reference to the former, and the chances are they will not work together. It is a bit like putting 89 octane fuel in a Formula 1 car: it may get you round the circuit, but the chances are you're not going to be very successful...

Calculating phosphorescence is documented in the manual: there is no reason to start worrying (in this particular context!) about radiative versus nonradiative transitions. For heavy elements, I think if you are using ECPs you have little alternative but to use the full spin-orbit operator. As I said above, effective one-electron operators like AMFI will not do.

Best regards
Pete

xiaolin wang
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### Re: Calculating spin-orbit matrix elements

Dear Pete
Than you for your advisement. I don't quite understand the spin-orbit coupling operator, and I have a lack of quantitative knowledge. I calculate one molecule containing Iridium atom by three methods. I am not sure whether the full spin-orbit operator use keyword .SPIN-ORBIT. I hope to get the correct answer. If what you said I undstand wroing, can you tell me full spin-orbit operator use which keyword? I have known my system possessing heay metal can not use AMFI poerator, because I find the result unreasonable. I find the result, computed by effective one-electron operators with ECP basis set, order of magnitude is what I want. I also calculate the same molecule by .SPIN-ORBIT keyword with ECP basis set, and the result order of magnitude is too small. I upload the outputs and inputs of two methods.

Thanks again and best regards!
xiaolin
Attachments
peng-1.mol
full_peng-1.out
full.dal
effectiveCoreOneElectron_peng-1.out
effectiveCoreOneElectron.dal

olav
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### Re: Calculating spin-orbit matrix elements

Please note that it only makes sense to use the full spin-orbit operator if you also have an all-electron wave function (i.e. not ECPs). Of the two calculations you provide only the second makes sense (EffectiveCoreOneElectron). Even so, this is such a crude approximation that the best you can hope for is a result with the correct order of magnitude. The Ir atom has here an effective semi-empirical charge of > 1000 to compensate for the lack of Ir core electrons in the wave function.

Regards,
Olav

taylor
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### Re: Calculating spin-orbit matrix elements

This (Olav) certainly clarifies what I already thought had been posted about spin-orbit and ECPs and heavy elements. But just out of interest (because I do very few fine-structure calculations, and even fewer heavy elements) what is the best procedure for someone who (say) wants to do calculations of fine structure in a platinum complex? Can they do anything useful with Dalton? Or should we be telling them up front that we don't have the technology (which frankly, setting aside our sister code DIRAC...) means no-one else has either!

Best regards
Pete

xiaolin wang
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### Re: Calculating spin-orbit matrix elements

Dear Olav and Pete
Thank you very much for your advisement. I feel sorry for my late reply. I feel difficult to understand the meaning behind the words of posts due to the lack of quantitative knowledge. I will now read the instruction carefully and learn new knowledge.

Best regards
xiaolin

xiaolin wang
Posts: 15
Joined: 20 Sep 2016, 04:06
First name(s): Folwe
Last name(s): wang
Affiliation: High University
Country: China

### Re: Calculating spin-orbit matrix elements

Dear everyone,
I have a question to consult with engineer and want to get your help. I need calculate the SOC matrix elemnet betweent ground and T1 state. I am not sure which configuration should be used in the input file. It will be greatly appreciated if I can get your kind help. Thank you.

Regards
xiaolin

qinghua
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Country: China

### Re: Calculating spin-orbit matrix elements

Dear everyone，
I would like to calculate spin-orbit matrix elements between excited states (S1 -> Tn), by the quadratic-response TDDFT approach, on systems containing heavy atoms. The SOC operator makes use of a semi-empirical effective single-electron approximation. The obtained results seems to be wrong. The attachment is the output. I also want to use Breit-Pauli method to calculate the spin-orbit matrix elements. How should my input file be modified?
Thank you very much and best regards!
Qinghua
Attachments

hjaaj
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First name(s): Hans Jørgen
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### Re: Calculating spin-orbit matrix elements

Dear Qunghua

2. Anyway, I have looked at your problem. Dalton detects that your molecule has C2 symmetry, and runs it in C2 symmetry which has two irreps.After the .ROOTS key word Dalton thus expects two numbers, telling how many roots you want in each symmetry. You only gave one number ("3"), this is the reason for the error exit. Alternatively you can request Dalton to run without symmetry with "Nosymmetry" the appropriate place in the .mol file, and then your .dal input is fine.

-- Hans Jørgen.

ndhieu92
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