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Why does Heliumhelium have such a low van der Waals coefficient but not as low a Lennard Jones-Jones coefficient?

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though helium should have the weakest $r^{-6}$ term of any atom, if you look up the experimental values of the Lennard-Jones coefficients, you find that they're the same for Helium as they are for the rest of the noble gases. 

What gives? Why is its Lennard-Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

Why does Helium have such a low van der Waals coefficient but not as low a Lennard Jones coefficient?

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though helium should have the weakest $r^{-6}$ term of any atom, if you look up the experimental values of the Lennard-Jones coefficients, you find that they're the same for Helium as they are for the rest of the noble gases. What gives? Why is its Lennard-Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

Why does helium have such a low van der Waals coefficient but not as low a Lennard-Jones coefficient?

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though helium should have the weakest $r^{-6}$ term of any atom, if you look up the experimental values of the Lennard-Jones coefficients, you find that they're the same for Helium as they are for the rest of the noble gases. 

What gives? Why is its Lennard-Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

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edit approved Sep 19, 2021 at 19:58
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edit approved Sep 19, 2021 at 19:58
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Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though Heliumhelium should have the weakest $r^{-12}$$r^{-6}$ term of any atom, if you look up the experimental values of the Lennard Jones-Jones coefficients, you find that they're the same for Helium as they are for the rest of the Nobelnoble gases. What gives? Why is its Lennard Jones-Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though Helium should have the weakest $r^{-12}$ term of any atom, if you look up the experimental values of the Lennard Jones coefficients, you find that they're the same for Helium as they are for the rest of the Nobel gases. What gives? Why is its Lennard Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though helium should have the weakest $r^{-6}$ term of any atom, if you look up the experimental values of the Lennard-Jones coefficients, you find that they're the same for Helium as they are for the rest of the noble gases. What gives? Why is its Lennard-Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)

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Why does Helium have such a low van der Waals coefficient but not as low a Lennard Jones coefficient?

Helium has the lowest polarizability of any atom, and therefore ought to have the smallest London dispersion force. Indeed, if you look at the van der Waals constant of helium, you find that it has the lowest value of $a$ by a lot. $a$ roughly corresponds to the amount attraction between particles.

The long-distance force between neutral particles can be roughly modelled by the Lennard-Jones potential. Even though Helium should have the weakest $r^{-12}$ term of any atom, if you look up the experimental values of the Lennard Jones coefficients, you find that they're the same for Helium as they are for the rest of the Nobel gases. What gives? Why is its Lennard Jones potential roughly the same when its London dispersion force is so weak? (Perhaps my source is just wrong?)