title: Marked influence of the nature of the chemical bond on CP-violating signature in molecular ions HBr(+) and HI(+).
abstract: Heavy polar molecules offer a great sensitivity to the electron electric dipole moment (EDM). To guide emerging searches for EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions HBr(+) and HI(+) in their respective ground X (2)Pi(3/2) states. We find that the energy corrections due to EDM for the two ions differ by an unexpectedly large factor of 15. We demonstrate that a major part of this enhancement is due to a dissimilarity in the nature of the chemical bond for the two ions: the bond that is nearly of ionic character in HBr(+) exhibits predominantly a covalent nature in HI(+). We conclude that because of this enhancement the HI(+) ion may be a potentially competitive candidate for the EDM search.
authors.affiliation: Department of Physics, University of Nevada, Reno, NV 89557, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Ravaine
authors.forename: Sergey G
authors.initials: SG
authors.lastname: Porsev
authors.forename: Andrei
authors.initials: A
authors.lastname: Derevianko