Experimental and theoretical studies of Lambda doublings and permanent electric dipoles in the low-lying (1)Pi states of NaCs

摘要

We present experimental data on the electric permanent dipole moments d(upsilon('),J(')) and Lambda splittings (q factors) in the quasidegenerate (3) (1)Pi(e/f) state of the NaCs molecule over a wide range of the vibrational (upsilon(')) and rotational (J(')) quantum numbers by using the combination of dc Stark mixing and electric radio frequency-optical double resonance methods. Within the experimental (3) (1)Pi state upsilon(') ranged from upsilon(')=0 to 34, q values exhibited a pronounced decrease from 7.91x10(-6) to 0.47x10(-6) cm(-1), while parallel to d parallel to values varied between 8.0 and 5.0 D. Experimental evaluation yielded small d values about 1 D for D(2) (1)Pi state upsilon(')< 3 levels. The experiment is supported by ab initio electronic structure calculations performed for the (1-3) (1)Pi states of NaCs by means of the many-body multipartitioning perturbation theory of potential energy curves, permanent dipole, and angular coupling matrix elements for the lowest singlet states. The predicted d values reproduce their experimental counterparts within the measurement errors while theoretical q factors reproduce the measured upsilon(') dependence being, however, systematically overestimated by ca. 1x10(-6) cm(-1). The present NaCs data are compared with those of the NaK and NaRb molecules. (c) 2006 AmericanInstitute of Physics.