ИСТИНА

The stimulated Raman adiabatic passage (STIRAP) is widely used to create alkali diatomic molecules in their absolute ground state. This two step optical process involves intermediate excited rovibronic states which should be singlet-triplet mixed to provide an appropriate efficiency of nominally forbidden singlet-triplet transitions from the uppermost levels of both singlet X1S+ and triplet a3S+ ground states [1]. In the case of alkali diatomics containing heavy atoms (such as Rb or Cs) spin-orbit coupling indeed leads to pronounced mutual perturbation of low-lying excited states. Moreover, due to the vicinity of atomic energies of the first excited 42P(K) and 52P(Rb) states electronic the structure of the KRb molecule is additionally perturbed by a strong radial coupling effect between states possessing the same spatial and spin symmetry[2]. Recently, we performed a local deperturbation analysis of the experimental rovibronic term values mainly belonging to the (1~2)1Π and 21Σ+~13Π complex of KRb [2,3]. In the present, work we significantly expand the examined energy manifold by involving the close-lying (1,2)1P, 13P, 21S+ and 23S+ states in the explicit coupled-channel (CC) deperturbation treatment simultaneously. Potential energy curves for isolated states of the (1~2)1P complex and relevant spin-orbit coupling (SOC) matrix elements were presented in a diabatic basis to simplify the numerical solution of the CC equations. The corresponding non-adiabatic eigenvalues and multichanneleigenfunctions were found using a finite-difference scheme combined with a Richrdson extrapolation to the zeroth step. Analytical mapping was applied to improve the efficiency of the solution [4]. Using predicted rovibronic energies, as well as radiative lifetimes and linewidths, calculated from high level ab initio transition dipole moments, we further reanalyzed transition probabilities of the optical cycle a3S+(v,J =0) -> [11Π~21Π~21Σ+~23S+~13Π](v*,J = 1) -> X1S+(v = 0,J = 0) for a wide range of the vibronic excitations. References [1] D. Borsalino, B. Londo˜no-Flor`ez, R. Vexiau, O. Dulieu, N. Bouloufa-Maafa, and E. Luc-Koenig, Phys. Rev. A, 90, 033413 (2014). [2] S.V. Kozlov, E.A. Pazyuk, and A.V. Stolyarov, Phys. Rev. A 94, 042510 (2016). [3] K. Alps, A. Kruzins, M. Tamanis, R. Ferber, E.A. Pazyuk, and A.V. Stolyarov, J. Chem. Phys. 144, 144310 (2016). [4] V.V. Meshkov, A.V. Stolyarov, and R.J. Le Roy Phys. Rev. A 78, 052510 (2008).