On the 1(A)1Σ+u → 1(X)1Σ+g emission of Na2 observed following the laser excitation of the 1(B)1Πu state

An emission clearly assigned to the 1(A)1Σ+u → 1(X)1Σ+g band system of Na2 has been recorded following the excitation of the 1(B)1Πu state by using different Ar+ laser lines. A whole simulation of the 1(A)1Σ+u → 1(X)1Σ+g emission profile, including bands with 0 ≤ ν' ≤ 30, 0 ≤ ν-prime ≤ 55 and J extended up to 50, shows that the 1(A)1Σ+u excited state is in a Boltzmann distribution owing to a rovibrational relaxation within this electronic state. This simulation suggests that the zone of maximum spectral emission does not correspond to the most intense transition but to a superposition of many individual bands for high vibrational levels of the 1(A)1Σ+u state. The 1(A)1Σ+u → 1(X)1Σ+g emission is similar whatever the laser wavelength used to excite the 1(B)1Πu state. Collisional energy transfer processes among different species are discussed. Further work is needed for the complete identification of the competitive energy transfer processes