Extended Data Fig. 3: Hückel energy level distribution for T–N–T displaying the active space of 24 MOs. | Nature Chemistry

Extended Data Fig. 3: Hückel energy level distribution for T–N–T displaying the active space of 24 MOs.

From: Quantum interference effects elucidate triplet-pair formation dynamics in intramolecular singlet-fission molecules

Extended Data Fig. 3: Hückel energy level distribution for T–N–T displaying the active space of 24 MOs.

The MRSDCI calculations are over an active space of MOs about the chemical potential that is smaller than the complete set. The lowest few bonding MOs are frozen (that is, excitations from these lowest MOs are not included in the CI calculations) and the highest MOs related to these by charge-conjugation symmetry are excluded from the active space. As of now, we have performed MRSDCI calculations over active spaces of 22–30 MOs, 11–15 bonding and 11–15 antibonding. These are absolutely the largest active spaces over which calculations of \(^1\left| {TT} \right\rangle\) have ever been done. We illustrate our procedure with the specific case of T–N–T. The localized tetracene Hückel bonding (red) and antibonding (blue) MOs, and the naphthalene (green) MOs constitute the active MO space in our T–N–T calculations. For calculations on T–Ph–T, T–A–T, P–Ph–P, P–N–P and P–A–P, we retained 20 + 4, 16 + 6, 20 + 4, 20 + 6 and 20 + 6 MOs, respectively, where the numbers in each sum indicate the chromophore MOs plus the linker MOs.

Back to article page