Spectroscopic investigation of the electronic structure of the chlorine molecule in the VUV

Rotational Analyses for Selected Bands of the 2 ← X1 Transition of Cl2

“…The dominant interaction between the diabatic 4pπ Rydberg state and the third tier ion-pair state that dissociates to Cl + ( 1 D g ) + Cl - ( 1 S g ) yields a lower energy adiabatic level (called 1 1 ), which has a double-well potential energy curve. This structure has now been satisfactorily characterized by several single-photon synchrotron − and VUV laser studies. − …”

“…The equilibrium bond length, r e ‘, of the 2-state is calculated to be r e ‘ ≈ 2.1 Å, which corresponds roughly to the r value of the top of the barrier separating the Rydberg and ion-pair portions of the 1-state. , However, to the best of our knowledge, no rotational analyses for the 2-X transition have ever been reported that can confirm this prediction. For this paper therefore, we have rotationally analyzed our published Cl 2 2-X VUV laser fluorescence excitation spectra, which were obtained using tunable, coherent, and monochromatic radiation generated by four-wave difference mixing in Kr gas …”

Ultraviolet photolysis and internal dynamics of molecular chlorine in an argon matrix at 4.2 K

“…When the present work was begun, the only unambiguous observations of highly excited states of Cl2 were the gas-phase synchrotron experiments of Moeller et al,7 who observed five singlet states lying in the region 9.05-10.05 eV above the ground state, and the electron impact spectra of Jureta et al8 in the range 2-14 eV. These results are in reasonable accord with the calculations of Peyerimhoff and Buenker6 which indicate that some of the upper states in question have double-minimum wells, and they also confirm the theoretical prediction6 of the existence of strong Coupling between Rydberg and valence states in this region.…”

Isotopic mass dependence in the bound–free D–X fluorescence spectrum of Br2

“…The diatomic halogen molecules all absorb vacuum-and extreme-ultraviolet radiation strongly, as they undergo transitions to ion-pair and Rydberg excited states (1)(2)(3)(4)(5)(6)(7)(8). The ion-pair states have their minima at significantly larger internuclear distance R than the R, of the ground states, so absorption into an ion-pair state populates very highly excited vibrational levels.…”