ИСТИНА

In recent years, ultracold alkali metal dimers have been found to have many promising implementations both in fundamental physics and quantum engineering. Amongst these are ultracold chemistry reactions, quantum information processing, and even the testing fundamental laws of physics. Li-containing heterodimers are particularly attractive candidates due to their high ground state dipole moment that makes it possible to manipulate them with external electric fields. However, to be able to utilize these molecules, one must first create a stable ensemble of ultracool ultracold molecules. One of the most widespread methods to accomplish this is the adiabatic transfer of ultracold Feschbach molecules from the lowest triplet electronic state to their absolute ground state (v=0, J=0). This transfer is a multistep process which a priori requires precise and comprehensive spectroscopic information on the involved electronic states. In this work, we performed a direct deperturbation analysis of all experimental term values of the B1 and C1+ states that have recently become available in the literature for the 6,7Li85,87Rb isotopologues [1-4]. The rigorous coupled-channel modeling Hamiltonian accounts for the local L-uncoupling effect between the crossing B1 and C1+ states explicitly while the regular interactions with the remote states manifold are introduced into the Hamiltonian by the 2-nd order van Vleck’s contact transformation. The initial set of the required interatomic potentials and L-uncoupling electronic matrix elements as a function of internuclear distance are obtained within the framework of high level ab initio electronic structure calculations [5]. The fitted non-adiabatic matrix elements and potential energy curves reproduce the overall experimental data of the interacting B1 and C1+ states with experimental accuracy (0.01 cm-1). Particular attention is paid to the probe mass-invariant properties of the deperturbed structure parameters. The study was funded by RFBR according to the bilateral Russia-Bulgaria research project 17-53-18006. References Journal [1] J. Chem. Phys. 2013, 138, 94315 [2] Chem. Phys. Lett. 2011, 7, 511, 7 [3] Rev. A, 2016, 94, 062503 [4] Phys. Rev. A, 2014, 90, 062513 [5] PCCP, 2018, 20, 1889