Perturbation and Predissociation near the Dissociation Limit of the BΠ State of ²³Na³⁹K

Abstract

The J′ dependencies of energy and line width of the 23 Na 39 K B 1 Π(V′ ) 30-43, J′) r X 1 Σ + (V′′ ) 2, J′′) transitions are measured up to the breaking-off points, where NaK dissociates to the Na(3s 2 S 1/2 ) + K(4p 2 P 3/2 ) atoms. Line broadenings are observed for transitions to the B 1 Π(V′ ) 30, J′ g 42), (V′ ) 31, J′ g 35), (V′ ) 32, J′ g 27), (V′ ) 33, J′ g 14), and (V′ g 34, all J′) levels, and are attributed to the predissociation via the c 3 Σ + state to the Na(3s 2 S 1/2 ) + K(4p 2 P 1/2 ) atoms. The (V′, J′) dependence of the predissociation threshold is attributed to the potential barrier due to rotation. Below and near the threshold, a series of the perturbation centers which converge to the predissociation threshold is observed for each V′, and the perturbing state is identified as the c 3 Σ + state. Rotational perturbations are observed also above the predissociation threshold, and the perturbing state is identified as the b 3 Π 1 state. The line widths are observed to change drastically around the maximum perturbation, and this is identified as originating from the interference effect which arises because both the B 1 Π and b 3 Π 1 states interact with the dissociative continuum of the c 3 Σ + state. In the transitions to levels near the breaking-off points of the B 1 Π(V′ g 37), the line splittings into two lines are observed for each J′. This splitting is identified as originating from the S-uncoupling interaction between the B 1 Π and b 3 Π states at a long internuclear distance. Similar line splittings are observed for the B 1 Π(V′ ) 30, all J′) levels, but are not observed for V′ ) 31-36. An accidental coincidence of the level energies of the B 1 Π(V′ ) 30) and b 3 Π(V) levels is presumed, and the origin of the line splitting is identified as the S-uncoupling interaction. This is confirmed by the analysis of the hyperfine structures observed for the split lines.

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

“…Actually, the observed interference pattern only constrains the sign of the product of three interactions: W (1) with E (0), W (1) with the continuum, and E (0) with the continuum; and other combinations of signs will produce the same width pattern. 41 The J-independent part of the W (1) predissociation broadening may arise from its electronic coupling to other 1 states and their mutual spin-orbit interaction with further states of 3 symmetry, 2, 13, 24 a process which has yet to be fully quantified. The assumed J-dependent interaction of W (1) with the continuum in Eq.…”

High resolution laser spectroscopy of the Cs2 C 1Πu state: Perturbation and predissociation

“…Wave functions of two interacting bound levels can mix either constructively or destructively for the interaction with a dissociative state. 15 This interference effect in quantum mechanics will be very important in the photodissociation.…”

Spectroscopic investigation of the A and 3 1Σ+ states of 39K85Rb

“…The vibrational levels of the 3 1 + state above the K(4s) + Rb(5p 1/2 ) limit may be predissociated. 34,35 Second, it is interesting to explore the boundary between the Hund's case (a) and Hund's case (c) behavior of various levels. According to Kotochigova et al, 31 abrupt boundaries between Hund's case (a) and Hund's case (c) are evident in the TDMs with respect to internuclear distance.…”

“…Moreover, exploring the energy region bluedetuned above the K(4s) + Rb(5p 1/2 ) asymptote should also be quite interesting, with many additional perturbations and predissociations. 35…”