Intramultiplet mixing

V INTRAMULTIPLET MIXING IN EXCITED ALKALI ATOMS UPON COLLISIONS WITH NOBLE-GAS ATOMS... 

VII INTRAMULTIPLET MIXING AND EXCITATION TRANSFER IN COLLISIONS OF EXCITED AND GROUND-STATE ALKALI ATOMS... 

Conditions of nearly adiabatic coupling are frequently met in atomic collisions. This will be exemplified in Section V for the collisionally induced intramultiplet mixing in alkalies. 

The theory of the intramultiplet mixing in alkalies M (2i3) in collisions with noble-gas atoms X(1S0),... 

Figure 5.8 Intramultiplet-mixing cross sections cr( - 2) (in A2) for different M -X pairs as a function of the effective temperature T = T ( m-Hc/ m-x).

Thus, the intramultiplet mixing in heavy alkalies can be accounted for by transitions in two nonadiabaticity regions that give competing contributions to the mixing cross sections. It seems clear now that an attempt [62] to interrelate experimental data resorting only to equation (57) cannot be justified. 

Under this condition a collision practically does not induce intramultiplet mixing, but during a collision there is an appreciable distortion of atomic functions. The mere fact of the existence of the molecular term A2ni/2 described by the Hund coupling scheme a means that the electronic spin follows rotation of the molecular axis. To this approximation there will be depolarization of the P1/2 state although the relevant molecular term... 

Due to these constraints, the number of independent parameters for transitions within the 2P doublet is eight (65). If, however, the discussion concerns only depolarization of 2PV2 and 2PZ/2 states independently, and total excitation transfer between sublevels j = and j = f, this number reduces to five one cross section for depolarization of the 2Pm state, three cross sections for depolarization of the 2P3/2 state, and the remaining cross section for the total intramultiplet mixing (see Section V). 

Nonresonant excitation transfer, that is, intramultiplet mixing, requires discussion of possible nonadiabatic regions. As seen from Figure 5.8 there are several pseudocrossings, crossings, and mergings, but selection rules... 

Intramultiplet mixing in K was found to be due mainly to nonadiabatic coupling near R0 m 15-22 a.u. between terms d 1 and cl, which arise from merging terms 3IIl0 and iniu of similar partners under the influence of a perturbation proportional to Ae,. — Ae, . The upper bound of the estimated... 

The recent trend in theoretical investigation of intramultiplet mixing and depolarization was represented by attempts to consider both types of processes in terms of the same collision model. We mention here only works published in 1972 and 1973 on processes... 

A.I.Voronin and E.E.Nikitin, Intramultiplet mixing cross sections for atoms of second column, Optika i Spektr. 25, 803 (1968)... 

E.I.Dashevskaya, E.E.Nikitin, and A.I.Resnikov, Theory of eollisionally indueed intramultiplet mixing in excited alkali atoms, J. Chem. Phys. 53, 1175 (1970)... 

E.E.Nikitiii, Intramultiplet mixing and depolarization ia atomic collisions, in Atomic physics IV, ed. G. zu Putlitz, New York, Plenum Press 1975, p.529... 

Yet another type of quasi-resonant processes corresponds to the so-called intramultiplet mixing, i.e. to transitions between fine-structure components of... 

---