Behavior of relative state selective photoionization cross sections of RbBr molecules in the valence region

The photon energy dependence of relative photoionization cross sections in the valence ionization energy region of 5 to 45 eV for $4p$ and $4s$ orbitals of Rb and Br ions in RbBr vapors has been investigated. The behavior of state selective cross sections of molecular valence orbitals has been analyzed by comparing the observed $4p$ to $4s$ photoelectron intensity branching ratios with atomic state selective photoionization cross sections of Kr, taking into account the mixing between Br $4s{}^{-1}$ and Rb $4p^{-1}$ molecular states. Using atomic dipole matrix elements to calculate the photoionization intensity of alkali halides has been suggested.

Figure 1

Experimental valence photoelectron spectrum of RbBr measured with 115 eV photon energy.

Figure 2

The $4p/4s$ intensity ratios of RbBr and Kr [20, 21] as a function of photon energy.

Figure 3

(a) Experimental inner-valence photoelectron spectra of RbBr measured with 45, 75, and 90 eV photon energies. (b) Theoretical spectrum, taken from Ref. [7], presented with vertical red bars.