Calcul théorique en couplage Λ-Σ du spectre électronique des excimères Ar2 et Kr2 corrélé aux configurations atomiques np5(n + 1) s et np5( n + 1) p

Abstract

2014 Les courbes de potentiel adiabatiques de Ar(3p6 1S0) + Ar* (3p5 4s, 3p5 4p) et de Kr (4p6 1S0) + Kr* (4p5 5s, 4p5 5p) sont déterminées en représentation 039B, par des calculs d'IC ab initio mettant en oeuvre des pseudopotentiels non empiriques et utilisant des bases d'orbitales étendues. Les croisements évités, avec des états corrélés à des configurations plus excitées, plus précisément 5s, 5p et 3d pour Ar*2, 6s, 6p et 4d pour Kr*2 sont également pris en compte. L'analyse de la nature des OM Rydberg et des fonctions d'onde multiconfigurationnelles permet d'interpréter la structure du spectre électronique de ces deux excimères et de comprendre le caractère des croisements évités entre états Rydberg des gaz rares homonucléaires. Abstract. 2014 Adiabatic potential curves for Ar (3p6 1S0) + Ar* (3p5 4s, 3p5 4p) and Kr(4p6 1S0) + Kr* (4p5 5s, 4p5 5p) are determined in the 039B representation, from ab initio CI calculations using non-empirical pseudopotentials and extensive orbital basis sets. Avoided crossings with states correlated to higher excited configurations, e.g. 5s, 5p and 3d for Ar*2 and 6s, 6p and 4d for Kr*2 are also taken into account. The structure of the electronic spectrum of both excimers is interpreted; analysing the nature of the Rydberg MO's and the multiconfigurational wave-functions makes possible the understanding of the character of avoided crossing between Rydberg states of homonuclear rare gases.

Rotational analysis of the 7pσ 3Σ+g←a3Σ+u system of the Ar2 molecule

“…Again, as expected, the best comparisons of theory to experiment are with the values from Ref. 31 which also produced the highest Devalue (see above). Finally, it should be noted that the most precise values for B;…”

Pressure broadening of 772.376 and 772.421 nm argon lines and kinetics of argon metastable atoms

“…Indeed, a realistic calculation of the van der Waals broadening must take into account the real molecular potentials of the interacting atoms, forming Ar*-Ar dimer. Ab-initio calculations on potentials of Ar2 * molecule have been carried out by several groups 60,61,62 . But, to our knowledge, that potentials have never been used for deducing the pressure broadening constants of argon lines.…”

Excited gerade states in Ne2and Kr2

“…A possible reason may be an avoided crossing of the Kr2(6p, 3Z8) potential curve with a repulsive curve Kr(5p)+Kr. According to the discussion of Spiegelmann and Gadea (1984) and Audouard (1990) such a crossing is to be expected. If this crossing is efficient in the region of the U' = 0 states with high rotational quantum numbers, these states will be broadened and therefore they will not contribute to the narrow absorption structure.…”