The quasimolecular 1s? orbital in collision systems?(Z 1+Z 2)?1, its excitation and spectroscopy

Abstract

An analytical formula for the excitation probability of the quasimolecular l sa orbital as a function of the impact parameter b is derived for collision systems with e(Z 1 +Z2)> 1. This formula describes well all existing experimental data for those collision systems except for the heaviest system Pb + Cm (Z 1 + Z 2 = 178) at impact parameters b <40 fm. It is discussed in which way energies of the quasimolecular l so-orbital can be extracted from experimental lso-vacancy production data.

K-shell ionization in 7.5- and 8.6-MeV/a.m.u. U+U collisions at very small impact parameters

“…This is a calculation of 2pu vacancy production including direct ionization and the coupling of a 2p 3 / 2 vacancy into the 2p 1 / 2 (u) MO The dashed line in Figure 3 is the result of a scaling law calculation which we have found to be reasonably accurate at larger impact parameters and also in lower energy U + U collisions (1]. The scaling law (15,16] gives the K-vacancy production probability, PKv, as a function of Ro(b)qo, where Ro is the distance of closest approach in the collision and…”

“…For 1su excitation we take m = 2 and F(Zu = 184) = 2 (16]. We also chose m = 2 for 2pu excitation here as it seems to fit these and other results [1,3] better than m = 2.5.…”

K-vacancy production in high-energy U+U and U+Pb collisions at small impact parameters

“…The solid lines represent the coupled-channel calculations of [6]. The top dashed line represents the scaling law prediction from [17], using a fitted, energy independent F factor [see Eq.…”

“…where m is approximately equal to 2 [17], and F(Z) is a constant (depending on the united-atom atomic number Z) which we treated as a fitting parameter.…”

“…7 and 8, we compare the values computed for P1s~ and P2v~ using Eqs. (20) and (21) with the scaling law [17] using Eq. (23) and with the ab initio calculations [6].…”