Configuration of Charge Waves in Polymethine Linear Dye Systems
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Table 1 Charge of the atoms and bond lengths in the polymethines 2–4 (n = 6)
№ Atom/bonds
2
3
4
R = OH
R = NH 2
R = OH
R = NH 2
Charge of atoms, q μ (a.u.)
1
−0.350
−0.385
−0.390
0.226
0.273
2
−0.181
−0.261
−0.260
−0.254
−0.360
3
−0.098
−0.208
−0.214
−0.025
−0.145
4
−0.251
−0.226
−0.226
−0.227
−0.288
5
−0.067
−0.210
−0.219
−0.020
−0.127
6
−0.269
−0.218
−0.220
−0.224
−0.297
7
−0.055
−0.202
−0.217
−0.018
−0.120
8
−0.269
−0.214
−0.217
−0.224
−0.297
9
−0.067
−0.176
−0.204
−0.020
−0.127
10
−0.251
−0.226
−0.225
−0.227
−0.288
11
−0.098
−0.151
−0.163
−0.025
−0.145
12
−0.181
−0.338
−0.319
−0.254
−0.360
13
−0.350
0.307
0.298
0.226
0.273
Bond lengths, L ν Å
1
1.3299
1.3644
1.3662
1.3576
1.3348
2
1.4525
1.4207
1.4140
1.4153
1.4350
3
1.3516
1.3865
1.3868
1.3648
1.3552
4
1.4257
1.4065
1.3993
1.4055
1.4196
5
1.3729
1.3918
1.3904
1.3770
1.3762
6
1.3987
1.4022
1.3977
1.3917
1.3975
7
1.3987
1.3886
1.3887
1.3917
1.3975
8
1.3729
1.3987
1.3997
1.3770
1.3762
9
1.4257
1.3853
1.3812
1.4055
1.4196
10
1.3516
1.3891
1.4028
1.3648
1.3552
11
1.4525
1.3967
1.3717
1.4153
1.4350
12
1.3299
1.3617
1.3994
1.3576
1.3348
As a result, disturbance at the ends of the chain caused by the insertion of the final
groups R1 and R2 generates its own wave of alternating (due to the factor (−1)
μ )
positive and negative charges at both ends of the collective π-electron system near
the heteroatoms. However, the amplitude of this wave rapidly decays, thanks to the
factor: 1/[π(2μ–1)]. Thus, the resulting curve of the graph |q μ | = f(μ) for the
polymethine chain of short molecules 1 should be interpreted as a superposition of
three waves: soliton charges in a circuit generated by the self-charged π-electron
system, as well as two waves that arise under the influence of finite groups.