Table 2.

Vertical excitation energies (VEEs) and oscillator strengths (f) of transitions to the lowest singlet and triplet excited states of B, calculated at the CASPT2/AVDZ level of theory.

Transition	Dominant orbital promotions	VEE/eV	f
S1-S0	6←4 (0.61); 7←5 (0.52); 6←5 (0.18)	4.09	0.0050
T1-S0	6←5 (0.89); 7←4 (0.18); 6←5+[7←4]2 (0.13)	2.42	0
T2-S0	6←4 (0.61); 7←5 (0.52); 6←5 (0.12)	3.82	0

The second column details the three orbital (see Supplementary Figure 3) promotions that make the largest contribution (expressed as coefficients in parentheses) to the respective excitations. [ ]² implies a double excitation.