Direct observation of the 2 ~3II_u state of Rb_2 in a pulsed molecular beam:Rotational branch intensity anomalies in the 2 ~3II_u (1_u)-X~1 sum_g~+(0_g~+)bands

摘要

Resonance enhanced two photon ionization study in a pulsed molecular beam identified spin-forbidden transitions of the 2 3~~( l~)—X ‘~~(0~ and 2 3fl1(0~ )—X ‘~7707 of Rb:. A-doubling and interference-induced rotational branch intensity anomalies are observed for 2 3fl, 1 ~ —X 1~(0) transitions. The rotational constant for the? ‘H,, state was determined to ~ Be=0.0189325±0.O0Q0074cm~’ for t5Rb,. giving R 4 9796~o.0009A. Other molecular parameters for t5Rb, are determined as Tj’19784.254250L?.009cm1. w,=e42.200±0.OO6cnf. wex,.0.171±0.001cm1. and WeYe=~~O.OOl 06±0.OOOO6cn< for the 2 ~fl,,(0[ state and T,,= 19785.74±0.01 cm’. We = 42.297±0.005 cmK w,.x, —0.1 725~0.0009 cm . and W,,Y,.—0.00078±0.00004cm1 for 2 3H,,~ I,,) state. These R,,. w~. and T, values agree well with oh irntio calculated values. The spin—orbit coupling constant A and A-doubling parameters p and q are determined by simultaneous fitting of the rotational structures of both 2 H,, (1,1 — X I~[ and 2 3H,,(07 )—X ~ transitions.