Question
This molecule composed of excited atoms was the first observed Rydberg molecule. For 10 points each:
[10h] Name this molecule, whose fully filled sigma-1s and sigma-star-1s molecular orbitals with no other MOs give it a bond order of zero. This molecule’s bond length of 5200 picometers makes it the largest diatomic molecule.
ANSWER: dihelium [or helium dimer; or He2; reject “helium”]
[10e] Despite having zero bond order in MO theory, dihelium is held together very weakly by these intermolecular forces named for a Dutch physicist. London dispersion and dipole-dipole interactions contribute to these forces.
ANSWER: van der Waals forces
[10m] Dihelium molecules have been observed to fit inside these other compounds in a host-guest relationship. These allotropes are denoted with the formula C-sub-x, where x is the number of atoms within the compound.
ANSWER: fullerenes [accept buckminsterfullerenes or buckyballs]
<Chemistry>
Summary
| 2024 ACF Winter at UC Berkeley | 2024-11-16 | Y | 3 | 23.33 | 100% | 100% | 33% |
| 2024 ACF Winter at Clemson | 2024-11-16 | Y | 8 | 13.75 | 100% | 38% | 0% |
| 2024 ACF Winter at Lehigh | 2024-11-16 | Y | 7 | 14.29 | 100% | 29% | 14% |
| 2024 ACF Winter at Northwestern | 2024-11-16 | Y | 9 | 14.44 | 100% | 44% | 0% |
| 2024 ACF Winter at Ohio State | 2024-11-16 | Y | 7 | 18.57 | 100% | 57% | 29% |
| 2024 ACF Winter at Online | 2024-11-16 | Y | 8 | 12.50 | 88% | 38% | 0% |
| 2024 ACF Winter at UBC | 2024-11-16 | Y | 2 | 10.00 | 100% | 0% | 0% |
| 2024 ACF Winter at Central Florida | 2024-11-16 | Y | 5 | 12.00 | 100% | 20% | 0% |
| 2024 ACF Winter at Oxford | 2024-11-16 | Y | 10 | 15.00 | 90% | 50% | 10% |
Data
| Bristol B | Durham B | 0 | 0 | 0 | 0 |
| Cambridge C | Bristol A | 0 | 10 | 10 | 20 |
| Durham A | Imperial B | 0 | 10 | 10 | 20 |
| LSE A | Cambridge B | 0 | 10 | 0 | 10 |
| Cambridge A | Manchester | 0 | 10 | 10 | 20 |
| Imperial A | Oxford A | 0 | 10 | 10 | 20 |
| Cambridge D | Oxford B | 10 | 10 | 10 | 30 |
| Vanderbilt | Edinburgh | 0 | 10 | 0 | 10 |
| Birmingham | Warwick A | 0 | 10 | 0 | 10 |
| Warwick B | LSE B | 0 | 10 | 0 | 10 |