Abstract
In this article, dynamic couplings for
X
-
A
,
X
-
C
, and
A
-
C
, by using first and second derivatives terms neglected in the Born-Oppenheimer approximation, are calculated. Newly calculated radiative transition probabilities for the
A
1
Σ
+
→
X
1
Σ
+
and
C
1
Σ
+
→
X
1
Σ
+
emission bands of
KH
are used to calculate the radiative and nonradiative lifetimes of the various vibrational levels
(
0
⩽
v
⩽
35
)
and
(
0
⩽
v
⩽
55
)
of
A
1
Σ
+
and
C
1
Σ
+
states of the diatomic potassium hydride,
KH
, molecule. For higher vibrational levels, an estimate of the bound-to-free emission probability is also needed and included. Accurate positions, radiative and nonradiative lifetimes of states belonging to the adiabatic
A
and
C
states of the
KH
molecule are estimated. The results come from a Fermi's Golden Rule treatment in coupling calculation. That confirms the accuracy reached in both approaches and also in the treatment of the diabatic-adiabatic transformation. It involves, in particular, an effective phase choice that is needed to properly estimate nonadiabatic couplings.