Table 4. Singlet–triplet energy gaps (kcal mol–1) for FP-1 partitions a .
| Acene | (n,m) | GASSCF |
GASPT2 |
tPBE (GAS-PDFT) |
Literature values
b
|
||||
| Vert. | Ad. | Vert. | Ad. | Vert. | Ad. | Vert. c | Ad. d | ||
| Naphthalene | (10,10) | 85.0 | 68.5 | 80.8 | 67.3 | 77.6 | 70.6 | 76.0 | 64.4 |
| Anthracene | (14,14) | 66.5 | 55.2 | 60.2 | 52.2 | 51.3 | 45.5 | 56.8 | 46.2 |
| Tetracene | (18,18) | 46.2 | 36.1 | 44.2 | 36.5 | 39.0 | 33.6 | 40.4 | 34.1 |
| Pentacene | (22,22) | 43.1 | 33.8 | 38.3 | 31.4 | 29.7 | 25.3 | 31.3 | 24.3 |
| Hexacene | (26,26) | 27.6 | 20.5 | 22.9 | 19.7 | 22.8 | 18.7 | ||
| Heptacene | (30,30) | 22.2 | 18.3 | 17.3 | 16.5 | 18.1 | 13.9 | ||
| Octacene | (34,34) | 11.8 | 9.1 | 12.4 | 12.4 | 13.4 | 11.5 | ||
| Nonacene | (38,38) | 10.9 | 8.3 | 11.4 | 11.8 | 10.7 | 10.4 | ||
| Decacene | (42,42) | 6.7 | 3.7 | 7.7 | 8.3 | 8.1 | 9.0 | ||
| Undecacene | (46,46) | 6.5 | 2.7 | 8.7 | 9.4 | 7.1 | 9.4 | ||
| Dodecacene | (50,50) | 4.9 | 0.18 | 5.9 | 6.8 | NA f | 8.9 | ||
| MUD e | 4.9 | 5.1 | 1.5 | 1.6 | |||||
aGeometries are optimized using B3LYP/6-31G(d,p) level of theory. GASSCF, GASPT2 and tPBE calculations are performed using 6-31+G(d,p) basis set.
bHighest-level available literature estimates.
cCCSD(T)/cc-pV∞Z from ref. 21.
dAverage adiabatic gaps from Table 1.
eMean unsigned deviation.
fNot available. For vertical excitations MUD is calculated for the values from naphthalene to undecacene only.