Environnement AF22e, Техническое руководство, Страница: 24 / 118

Environnement
S.A
AF22e
Duplication prohibited
APRIL 2016
2–4
From E
e1
, the molecule can return to any ground state sub level following different paths:
−
by fluorescence:
SO * SO hv'
2
Kf
2
⎯ → ⎯ +
Based on the above formula,

Firstly, v' =
c
λ
'
is less than v, therefore
λ
' >
λ
,

Secondly,
λ
' value follows a temperature dependent statistical distribution centered around an
average wavelength.
The analyzer "monitors" photons emitted through a filter centered on 350 nm.
−
by extinction
where M represents another gaseous molecule.
Then, the molecule scatters its energy mechanically and does not fluoresce. This phenomenon is
known as « quenching ».
−
by dissociation
Kd
2
SO * SO O
⎯⎯⎯ → +
The energy E
e1
is sufficient to break the SO
−
O link.
Kf, Kd, Kq stand for quantum yields associated with each form of deactivation. Linked to the state
E
e1
lifetime, they express probabilities associated with each reaction type. They are determined by
the whole space integral of the wave function product of the excited and fundamental states.
Kq
2 2
SO * M SO M
+ ⎯⎯⎯ → +