TABLE 1.
S0 (11Ag–) → S2 (11Bu+) |
S1 (21Ag–) → S0 (11Ag–) |
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solvent | n | R(n) | N = 4 | N = 5 | N = 6 | N = 7 | N = 4 | N = 5 | N = 6 | N = 7 |
pentane | 1.357 50 | 0.219 32 | 32 370 ± 4 | 29 360 ± 9 | 27 092 ± 4 | 25 320 ± 4 | 27 772 ± 12 | 24 244 ± 10 | 21 384 ± 21 | 19 183 ± 1 |
hexane | 1.375 06 | 0.22895 | 32 287 ± 11 | 29 268 ± 4 | 26 976 ± 4 | 25 195 ± 2 | 27 770 ± 6 | 24 253 ± 10 | 21 397 ± 25 | 19 210 ± 2 |
heptane | 1.387 77 | 0.235 85 | 32 233 ± 5 | 29 213 ± 2 | 26 939 ± 9 | 25 167 ± 6 | 27 775 ± 9 | 24 241 ± 10 | 21 363 ± 27 | 19 172 ± 2 |
isoctane | 1.391 50 | 0.237 86 | 32 284 ± 4 | 29 278 ± 3 | 26 999 ± 4 | 24 259 ± 10 | 21 392 ± 24 | |||
octane | 1.397 40 | 0.241 03 | 32 178 ± 12 | 29 171 ± 4 | 26 886 ± 5 | 25 102 ± 6 | 27 727 ± 20 | 24 248 ± 10 | 21 358 ± 31 | 19 218 ± 1 |
nonane | 1.405 40 | 0.245 31 | 32 136 ± 8 | 29 131 ± 6 | 26 820 ± 2 | 25 063 ± 4 | 27 743 ± 15 | 24 240 ± 10 | 21 360 ± 28 | |
tridecane | 1.425 60 | 0.256 01 | 32 028 ± 4 | 26 720 ± 4 | 21 347 ± 23 | |||||
pentadecane | 1.431 50 | 0.259 11 | 19 220 ± 3 | |||||||
hexadecane | 1.434 50 | 0.260 68 | 31 975 ± 3 | 28 926 ± 3 | 24 897 ± 7 | 27 759 ± 13 | 24 232 ± 10 | 19 224 ± 2 | ||
benzene | 1.501 10 | 0.294 67 | 31 572 ± 5 | 28 599 ± 5 | 26 305 ± 4 | 24 540 ± 4 | 27 694 ± 9 | 24 161 ± 10 | 21 257 ± 28 | 19 149 ± 2 |
gas phase | 1.008 | 0.005 33 | 34711 ± 8 | 31 805 ± 10 | ||||||
vacuum27,28 | 1 | 0 | 34 783 ± 3 |
N is the number of π-electron conjugated double bonds. The state energies were determined from the spectral origins (0–0) of the S0(11Ag–) → S2 (11Bu+) absorption and S1 (21Ag–) → S0 (11Ag–) emission. R(n) = (n2 – 1)/(n2 + 2) is the solvent polarizability, where n is the index of refraction of the solvent. The uncertainties represent ±1σ from the mean of a set of Gaussian fits to the absorption and emission spectra.