Fig. 6.13) and energy of transitions to the I 2 (E, v E = 0–6, J E = 0) states. Excitation
spectra of the UV luminescence measured in the m 1 = 17819.0–17812.6 cm
−1
spectral range are given in Fig. 6.14.
Spectrum (1) measured at m 1 = 17819.0 cm
−1 corresponds to a bound-free
B f← X transition in the complex with subsequent dissociation to the I 2 (B,
19) + He. Another (2)–(5) spectra are broad and correspond to the bound-bound
B ← X transition in the complex (see Fig. 6.8) and [37]). The bands in the
m 2 = 23549–23553 cm
−1 range become more and more distinct with m 1 decreasing
and in the m 1 < 17814.2 cm
−1 spectral range positions of the band maxima independent of m 1 value [89].
The I 2 (D ! X, E ! B) and very weak luminescence, k
max
lum % 342 nm, br.
r. % 0.03 and 0.02 at v E = 0 and 6 bands, respectively, occur. The HeI 2 (E,v E ,
Fig. 6.13 Survey excitation spectra of luminescence in the E ! B, k lum % 4284 Å, (red (grey)
line) and UV spectral range, k lum % 2600–3800 Å (black line) measured at k 1 = 5614.47 Å
(m 1 = 17811.1 cm
−1
, free-rotor HeI 2 (B,19,n B % 3 ← X,0,n X = 0,1) transition, see Fig. 6.8). Energy
of transitions to the I 2 (E,v E = 0–6,J E = 0) states corresponding to the most intense spectral m
1
f ¼
9395:12 cm
À1 component (dissociation limits of the HeI 2 (E,v E = 0-6,n E ) complexes) are marked
out as black squares. The bands corresponding to the I 2 (E,v E = 0-5 ← B,v B = 17,18 and b1 g ,
v b = 5-7 ← B,v B = 17,18) transitions are shown. Groups of excitation bands of the I 2 (IP ! valence
states) luminescence corresponding to the HeI 2 (E,v E = 0-6,n E ) states and located lower than the
corresponding dissociation limits of the HeI 2 (E,v E = 0-6,n E ) complexes are marked out as v E = 0-6
(see [89]) (Baturo, V.V., Lukashov, S.S, Poretsky, S.A., Pravilov, A.M., Zhironkin A.I.: The HeI 2
van der Waals complexes in a ‘free-rotor’ configuration. J. Phys. B: At. Mol. Opt. Phys. 53,
035101 (8 pp) (2020) https://doi.org/10.1088/1361-6455/ab582b. © IOP Publishing. Reproduced
with permission. All rights reserved)
222
6 Weakly-Bound Complexes and Clusters
spectra of the UV luminescence measured in the m 1 = 17819.0–17812.6 cm
−1
spectral range are given in Fig. 6.14.
Spectrum (1) measured at m 1 = 17819.0 cm
−1 corresponds to a bound-free
B f← X transition in the complex with subsequent dissociation to the I 2 (B,
19) + He. Another (2)–(5) spectra are broad and correspond to the bound-bound
B ← X transition in the complex (see Fig. 6.8) and [37]). The bands in the
m 2 = 23549–23553 cm
−1 range become more and more distinct with m 1 decreasing
and in the m 1 < 17814.2 cm
−1 spectral range positions of the band maxima independent of m 1 value [89].
The I 2 (D ! X, E ! B) and very weak luminescence, k
max
lum % 342 nm, br.
r. % 0.03 and 0.02 at v E = 0 and 6 bands, respectively, occur. The HeI 2 (E,v E ,
Fig. 6.13 Survey excitation spectra of luminescence in the E ! B, k lum % 4284 Å, (red (grey)
line) and UV spectral range, k lum % 2600–3800 Å (black line) measured at k 1 = 5614.47 Å
(m 1 = 17811.1 cm
−1
, free-rotor HeI 2 (B,19,n B % 3 ← X,0,n X = 0,1) transition, see Fig. 6.8). Energy
of transitions to the I 2 (E,v E = 0–6,J E = 0) states corresponding to the most intense spectral m
1
f ¼
9395:12 cm
À1 component (dissociation limits of the HeI 2 (E,v E = 0-6,n E ) complexes) are marked
out as black squares. The bands corresponding to the I 2 (E,v E = 0-5 ← B,v B = 17,18 and b1 g ,
v b = 5-7 ← B,v B = 17,18) transitions are shown. Groups of excitation bands of the I 2 (IP ! valence
states) luminescence corresponding to the HeI 2 (E,v E = 0-6,n E ) states and located lower than the
corresponding dissociation limits of the HeI 2 (E,v E = 0-6,n E ) complexes are marked out as v E = 0-6
(see [89]) (Baturo, V.V., Lukashov, S.S, Poretsky, S.A., Pravilov, A.M., Zhironkin A.I.: The HeI 2
van der Waals complexes in a ‘free-rotor’ configuration. J. Phys. B: At. Mol. Opt. Phys. 53,
035101 (8 pp) (2020) https://doi.org/10.1088/1361-6455/ab582b. © IOP Publishing. Reproduced
with permission. All rights reserved)
222
6 Weakly-Bound Complexes and Clusters