High-resolution electron-momentum spectroscopy of the valence orbitals of the iodine molecule

Abstract

The valence orbitals of the iodine molecule (I 2 ) have been studied using the high-resolution electron-momentum spectroscopy at impact energies of 1200 and 600 eV. Experimental momentum distributions of outer valence orbitals were compared with the nonrelativistic, scalar relativistic, and spin-orbital relativistic calculations, as well as the relativistic pseudopotential calculation. The experimental cross-section ratios of 8J 3/2 g to 17J 1/2 g , 8J 3/2 u to 16J 1/2 u , and the electron-momentum profiles of orbital 16J 1/2 g clearly manifested the relativistic effects. In the inner valence region, the symmetry-adapted-cluster configuration-interaction theory was used to interpret the ionization spectrum and the electron-momentum distributions.

Single ionization of molecular iodine

“…Figure 9 shows the potential energy curves for the low-lying states of I 2 and I are shown as blue dots and labeled as in [31].…”

“…4 and the ionization potentials and dissociation limits of iodine we can put limits on the KER we expect to see. The ionization potentials of I 2 have been measured using electron-momentum spectroscopy (EMS) and photo-electron spectroscopy (PES) [31,44].…”

“…Some possible combinations of the dissociation of I 2 to atomic fragments. DL is the dissociation limit as labeled in [30] and I p is the atomic ionization potential level as labeled in [31] where level 5 corresponds to the B state of I + 2 . We have average the D2, D3, and D7 manifolds.…”

“…In this paper, we take a different approach and look at a heavy diatomic molecule -iodine. Like the light polyatomic molecules, I 2 has low-lying accessible molecular orbitals [30,31]. However, its nuclear motion is very slow, due to its large mass and we can cleanly decouple ionization from dissociation.…”

Photoionization and Photofragmentation Dynamics of I2 in Intense Laser Fields: A Velocity-Map Imaging Study

“…Precisely assigning the origins for these different photodissociation channels is challenging, as there are a multitude of dissociative electronic states which may be populated (and which are not fully characterized in the literature) and various product channels to which these states could correlate. The vertical ionization energies to several cationic states have been measured previously using electron momentum spectroscopy and photoelectron spectroscopy . Thus, asymptotic KERs for dissociation pathways can be predicted from energy conservation considerations using these vertical ionization energies along with known possible product internal energies: normalK normalE normalR = normalV normalI normalE − ( E I + E I + + I p + D e ) where VIE is the relevant vertical ionization energy of I 2 , E I and E normalI + are the internal energies of the I and I + photoproducts respectively, I p is the ionization potential of ground-state I atoms (10.45 eV), and D e is the dissociation energy of I 2 (1.54 eV).…”