Isotopologue-selective excitation studied via optical-optical double resonance using the E3Σ1+(63S1)←A3Π0+(53P1)←X1Σ0+(51S0) transitions in CdAr and CdKr van der Waals complexes

A method of experimental selection of molecular isotopologues using optical-optical double resonance (OODR) scheme and supersonic beam source of van der Waals (vdW) complexes is presented. Due to an appropriately large isotopic shift, the proper choice of a wavenumber of a sufficiently narrowband laser in the first transition of OODR scheme can lead to a selective isotopologue excitation to the intermediate state. Thanks to this approach, it is possible to select some of the isotopologues which subsequently give a contribution to laser induced fluorescence (LIF) signal originated from the final state of OODR. In this article, results of tests of the proposed method that employs the E^3Sigma_1←A^3Pi_0+←X^1Sigma_0+ transitions in two vdW complexes, CdKr and CdAr, are presented and analysed.