Table 1 Relative energies
ΔE (in eV) with respect to the lowest ground-state minimum. Energies at the Franck–Condon (FC) point are vertical excitation
energies of the lowest singlet
π !
π* transition (best estimates given boldface in parentheses). Energies of optimized MECI structures refer to conical
intersections between the
S
1 and
S
0 states. The MRCISD, SSR, and SF data are taken from [59]
Geometry
MRCI
a
SSR
b
SF
c
TD
d
Geometry
MRCI
SSR
SF
TD
Ethylene
Methyliminium
FC point
e
(7.80) [99]
8.11
7.55
7.70
7.53
FC point
9.52
8.62
9.22
8.32
tw-pyr MECI
4.79
4.96
4.82
4.73
tw-BLA MECI
3.82
3.83
4.27
4.14
eth MECI
f
4.69
3.96
4.52
4.26
meth MECI
g
5.63
4.54
5.46
5.22
Styrene
Penta-2,4-dieniminium cation, PSB3
FC point
(4.88) [100]
5.76
5.10
5.29
5.25
trans-FC point
k
4.47
4.18
4.43
4.97
tw-pyr CI
1
h
4.68
4.29
4.01
n.a.
i
ΔE
S0
cisÀtrans
l
0.16
0.15
0.13
0.14
tw-pyr CI
2
j
5.28
4.97
4.83
4.72
cis-FC point
m
(4.20) [101]
4.24
4.08
4.28
4.93
tw-BLA MECI
2.38
3.00
3.08
2.82
Butadiene
Ketene
trans-FC point
n
(6.18) [99]
6.89
5.76
5.94
6.43
FC point
(3.84) [102]
4.01
3.93
4.01
4.06
ΔE
S0
cisÀtrans
l
0.07
0.14
0.11
0.14
MECI
2.43
3.00
2.82
3.27
cis-FC point
m,o
6.68
5.54
5.96
6.05
transoid MECI
4.89
5.58
5.19
5.40
Stilbene
Anionic HBI
trans-FC point
k
(4.1) [103]
(5.35)
q
4.18
4.35
4.42
FC point
(3.06) [104]
(3.88)
p
3.00
3.14
3.56
ΔE
S0
cisÀtrans
l
(0.13)
0.18
0.35
0.33
tw-pyr MECI
Im
q
(2.87)
2.97
2.84
2.60
cis-FC point
m
(4.6) [103]
(5.74)
4.54
4.49
4.86
tw-pyr MECI
ph
r
(3.20)
3.24
3.20
2.81
tw-pyr MECI
(4.50)
4.26
4.20
n.a.
i
462
M. Huix-Rotllant et al.