6.3.4.1 H 2 I 2 vdW Complexes
J.E. Kenny et al. [123] studied fluorescence excitation as well as fluorescence
spectra of ortho- and para-H 2 I 2 (B0
þ
u ,v B = 16, 20-23, 26,27) and D 2 I 2 (B0
þ
u ,v B = 16,
20-23, 26,27) complex VP products. They determined Morse potential parameters
for the ground- and B-state of the H 2 I 2 and D 2 I 2 complexes (Table 6.12).
The vdW frequencies, x e , and the energy gaps between the n = 0 and 1 vdW
levels, DE 01 , are much larger than those for the NeI 2 valence and E state, for
example (see Sect. ‘The NeI 2 complexes’ and Table 6.9). The authors of [124]
believed that this feature is due to small H 2 , D 2 masses (one should note that the He
atoms mass is small, also). The H 2 I 2 (B) state VP lifetime is short, * 18 ps, since,
as the author believed, vdW stretching frequency is well matched to that of the
I 2 (B) stretching frequency (x e = 128 cm
−1 ) that leads to good coupling between the
initial bound state and the final dissociative state. According to [124], VP lifetime
is * 29 ps for the H 2 I 2 (B,v B = 17) state.
6.3.4.2 N 2 I 2 vdW Complexes
According to [125], the binding energies of the N 2 I 2 (X,v X = 0), and N 2 I 2 (B,v B = 21)
states are 218 cm
−1
D
X;0
0
313 cm
−1 and 198 cm
−1
D
B;21
0
284 cm
−1 ,
respectively.
Detailed studies of some spectroscopic characteristics as well
electronically-excited state decay of the N 2 I 2 (X, B and E) complexes were carried
out in the author’s scientific group [126]. An algorithm of the first experiments was
the following. Initially, we measured the excitation spectra of luminescence of the
I 2 (B,19) and products of VP of the HeI 2 (B,19) and N 2 I 2 (B,19) complexes. One sees
the uncomplexed I 2 (B,19) band, bands corresponding to the T-shaped and free-rotor
Table 6.12 Morse potential
parameters for the groundand B-state of the H 2 I 2 and
D 2 I 2 complexes. Dissociation
(D e ) and binding (D 0 )
energies of the states, and
energy gaps between the
n = 0 and 1 vdW levels
(DE 01 ) [123]
X,v X = 0
B,v B = 28
x e (H 2 )
130.8
106.3
x e (D 2 )
92.5
75.2
x e x e (H 2 )
28.4
23.2
x e x e (D 2 )
14.2
11.6
D e (H 2 )
150.6
121.8
D e (D 2 )
150.6
121.8
D 0 (H 2 )
92.3
74.4
D 0 (D 2 )
107.9
87.1
DE 01 (H 2 )
74.0
59.9
DE 01 (D 2 )
64.1
52.0
6.3 Van der Waals Complexes
247
J.E. Kenny et al. [123] studied fluorescence excitation as well as fluorescence
spectra of ortho- and para-H 2 I 2 (B0
þ
u ,v B = 16, 20-23, 26,27) and D 2 I 2 (B0
þ
u ,v B = 16,
20-23, 26,27) complex VP products. They determined Morse potential parameters
for the ground- and B-state of the H 2 I 2 and D 2 I 2 complexes (Table 6.12).
The vdW frequencies, x e , and the energy gaps between the n = 0 and 1 vdW
levels, DE 01 , are much larger than those for the NeI 2 valence and E state, for
example (see Sect. ‘The NeI 2 complexes’ and Table 6.9). The authors of [124]
believed that this feature is due to small H 2 , D 2 masses (one should note that the He
atoms mass is small, also). The H 2 I 2 (B) state VP lifetime is short, * 18 ps, since,
as the author believed, vdW stretching frequency is well matched to that of the
I 2 (B) stretching frequency (x e = 128 cm
−1 ) that leads to good coupling between the
initial bound state and the final dissociative state. According to [124], VP lifetime
is * 29 ps for the H 2 I 2 (B,v B = 17) state.
6.3.4.2 N 2 I 2 vdW Complexes
According to [125], the binding energies of the N 2 I 2 (X,v X = 0), and N 2 I 2 (B,v B = 21)
states are 218 cm
−1
D
X;0
0
313 cm
−1 and 198 cm
−1
D
B;21
0
284 cm
−1 ,
respectively.
Detailed studies of some spectroscopic characteristics as well
electronically-excited state decay of the N 2 I 2 (X, B and E) complexes were carried
out in the author’s scientific group [126]. An algorithm of the first experiments was
the following. Initially, we measured the excitation spectra of luminescence of the
I 2 (B,19) and products of VP of the HeI 2 (B,19) and N 2 I 2 (B,19) complexes. One sees
the uncomplexed I 2 (B,19) band, bands corresponding to the T-shaped and free-rotor
Table 6.12 Morse potential
parameters for the groundand B-state of the H 2 I 2 and
D 2 I 2 complexes. Dissociation
(D e ) and binding (D 0 )
energies of the states, and
energy gaps between the
n = 0 and 1 vdW levels
(DE 01 ) [123]
X,v X = 0
B,v B = 28
x e (H 2 )
130.8
106.3
x e (D 2 )
92.5
75.2
x e x e (H 2 )
28.4
23.2
x e x e (D 2 )
14.2
11.6
D e (H 2 )
150.6
121.8
D e (D 2 )
150.6
121.8
D 0 (H 2 )
92.3
74.4
D 0 (D 2 )
107.9
87.1
DE 01 (H 2 )
74.0
59.9
DE 01 (D 2 )
64.1
52.0
6.3 Van der Waals Complexes
247