Bonus

A many-electron system’s state can be represented with a reduced form of this matrix for two electrons rather than with the full wave function. For 10 points each:
[10m] Name this matrix that is constructed by summing the outer products of state vectors. This matrix is often used to represent mixed states.
ANSWER: density matrix [or density operator; accept two-electron reduced density matrix; prompt on 2-RDM]
[10e] Methods based on the two-electron density matrix, or 2-RDM methods, compute this state for many-electron systems. In QM, electrons can absorb energy to transition from this state to an excited state.
ANSWER: ground state
[10h] Two answers required. A 2-RDM method resolved a discrepancy concerning energy barriers to these two possible pathways for the ring opening of two butadiene derivatives. These terms describe the ways end carbons are repositioned when a sigma bond forms.
ANSWER: disrotatory AND conrotatory [accept suprafacial AND antarafacial]
<Chemistry>
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TournamentExact Match?HeardPPBEasy %Medium %Hard %
2025 ACF NationalsYes2415.42100%33%21%