More examples

[Physfock]

Can authors add more examples of calculating some classical systems like muonic/antiprotonic helium?

[fsmoncadaa]

I'm not sure what you mean by classical. But, If I had to get a starting point for muonic/antiprotonic helium I would use an input like the attached file, where in the XXXXXX I would put the reduced mass of muonic helium (201.1) or of antiprotonic helium (1466.8), and rename it to have .lowdin extension He-e-X-CUSTOM_MASS.txt

This is a simple HF calculation, where the mass of the negative particle is given directly from the input. The large even-tempered basis set should provide coverage for the highly localized densities of the muon and antiproton.

with m=201.1 I got TOTAL ENERGY = -402.696687921461 VIRIAL RATIO (V/T) = 2.000024358632

and with m=1466.8 TOTAL ENERGY = -2926.149607172766 VIRIAL RATIO (V/T) = 2.007799376011

[Physfock]

I'm not sure what you mean by classical. But, If I had to get a starting point for muonic/antiprotonic helium I would use an input like the attached file, where in the XXXXXX I would put the reduced mass of muonic helium (201.1) or of antiprotonic helium (1466.8), and rename it to have .lowdin extension He-e-X-CUSTOM_MASS.txt

This is a simple HF calculation, where the mass of the negative particle is given directly from the input. The large even-tempered basis set should provide coverage for the highly localized densities of the muon and antiproton.

with m=201.1 I got TOTAL ENERGY = -402.696687921461 VIRIAL RATIO (V/T) = 2.000024358632

and with m=1466.8 TOTAL ENERGY = -2926.149607172766 VIRIAL RATIO (V/T) = 2.007799376011

Thanks for the answer! Following your example, I got a satisfactory value for the ground state of the muonic helium atom. The input below results in: -402.603948593154 a.u. while Hylleraas approach (exact variational solution for 3-body atomic problem) gives - 402.637332175538 a.u. (http://dx.doi.org/10.1051/epjconf/201922203009)

I slightly modify your suggestion as follows:

SYSTEM_DESCRIPTION='HeU Atom'

GEOMETRY e-[He] aug-cc-pVQZ 0.0000 0.0000 0.0000 multiplicity=2 addParticles=-1 U- 13s.ET.HE.U.TF 0.0000 0.0000 0.0000 m=201.1 He dirac 0.0000 0.0000 0.0000 END GEOMETRY

TASKS method = "UHF" configurationInteractionLevel ="FCI" END TASKS

However, I could not understand why in the manual (right at the beginning) when calculating "muonic water" the reduced mass for the muon never appears in the input geometry?

[fsmoncadaa]

Hi,

I'm glad that you found a input that is working

Our manual unfortunately is a bit outdated. In the next update we will add the reduced mass option to the input description figure. Thanks for pointing this out