Timeline for What do the indices mean in an FCIDUMP file?
Current License: CC BY-SA 4.0
13 events
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| Aug 6, 2020 at 4:16 | comment | added | fagd | Could you be slightly more explicit how to get "1221 in the paper is the same as 2211 in our output files"? I think that would be useful. So I think 11 in 2211 means spin up and down in the first orb, which will then be 10 in the paper, right? | |
| Aug 6, 2020 at 3:56 | comment | added | fagd | interesting, let me think abt it... | |
| Aug 6, 2020 at 3:54 | comment | added | Nike Dattani - No Free Time | There's also no 4 in the FCIDUMP either. Think about my last comment :) In fact the FCIDUMP has 7 lines instead of 4 x 4 x 4 x 4 = 256. | |
| Aug 6, 2020 at 3:53 | comment | added | fagd | I mention subtract 1, because I am confused by your comment "⟨𝑖𝑗|𝑘𝑙⟩=⟨𝑘𝑗|𝑖𝑙⟩, so 1221 in the paper is the same as 2211 in our output files". The labeling in the paper starts from 0, while that in the fcidump starts from 1, so I don't understand how you make the connection. For example, there is no 0 and 3 indices in the fcidump (not in the two-body integral). | |
| Aug 6, 2020 at 3:47 | comment | added | Nike Dattani - No Free Time | No if we were subtracting 1 from the indices, then the two 1-electron integrals would have to be equal, but they're not! | |
| Aug 6, 2020 at 3:45 | comment | added | fagd | So in short, we have the symmetry $\langle ij|kl\rangle = \langle ji|lk\rangle = \langle kj|il\rangle $. Do we need any other symmetries? | |
| Aug 6, 2020 at 3:41 | comment | added | fagd | Also the labeling of the paper starts from 0, while fcidump file starts from 1. So we cannot directly use the symmetry, we have to subtract 1 as well. | |
| Aug 6, 2020 at 3:40 | comment | added | Nike Dattani - No Free Time | You also have to enforce that if the integral is real-valued (meaning it has no imaginary parts), then the integral equals its complex conjugate. | |
| Aug 6, 2020 at 3:35 | comment | added | fagd | How did you arrive at ⟨𝑖𝑗|𝑘𝑙⟩=⟨𝑘𝑗|𝑖𝑙⟩? If I use the definition of ⟨𝑖𝑗|𝑘𝑙⟩ in theochem.github.io/horton/2.0.2/user_hamiltonian_io.html, I can only have ⟨𝑖𝑗|𝑘𝑙⟩=⟨𝑗i|𝑙k⟩, if I keep x_{1,2} not touched. Please let me know if this is just a simple algebra. I am doing the checking now. | |
| Aug 6, 2020 at 3:25 | comment | added | Nike Dattani - No Free Time | Don't forget that $\langle ij | kl \rangle = \langle kj | il \rangle$, so 1221 in the paper is the same as 2211 in our output files :) | |
| Aug 6, 2020 at 3:24 | history | edited | Nike Dattani - No Free Time | CC BY-SA 4.0 |
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| Aug 6, 2020 at 3:24 | comment | added | fagd | Sure. I would be happy to do that, and I have spent the whole day for that. The symmetry I know is <ij|kl> = <ji|lk>. And for the indices 1111, the first two has to be for spin up and down, and similarly for the latter two. That means it should corresponds to 0110 (It is not 1001 for convention I guess), where 0, 1 are for spin up and down in the 1st spin-orb. This is the same as 1001 using the symmetry above. Similarly 2222 would be 2332 and 3223. The 1100 and 2200 is easy. And the 1122, 2211, 2121 I am not quite sure. | |
| Aug 6, 2020 at 3:17 | history | answered | Nike Dattani - No Free Time | CC BY-SA 4.0 |