Interactions between anionic and neutral bromine and rare gas atoms

Abstract

High-quality, ab initio potential energy functions are obtained for the interaction of bromine atoms and anions with atoms of the six rare gases (Rg) from He to Rn. The potentials of the nonrelativistic (2)Sigma(+) and (2)Pi electronic states arising from the ground-state Br((2)P)-Rg interactions are computed over a wide range of internuclear separations using a spin-restricted version of the coupled cluster method with single and double excitations and noniterative correction to triple excitations [RCCSD(T)] with an extrapolation to the complete basis set limit, from basis sets of d-aug-cc-pVQZ and d-aug-cc-pV5Z quality. These are compared with potentials derived previously from experimental measurements and ab initio calculations. The same approach is used also to refine the potentials of the Br(-)-Rg anions obtained previously [Buchachenko et al., J. Chem. Phys. 125, 064305 (2006)]. Spin-orbit coupling in the neutral species is included both ab initio and via an atomic approximation; deviations between two approaches that are large enough to affect the results significantly are observed only in the Br-Xe and Br-Rn systems. The resulting relativistic potentials are used to compute anion zero electron kinetic energy photoelectron spectra, differential scattering cross sections, and the transport coefficients of trace amounts of both anionic and neutral bromine in the rare gases. Comparison with available experimental data for all systems considered proves a very high precision of the present potentials.

Mobilities of mixtures of ion isotopes in gas mixtures

“…The equations above were tested by calculating K 0 from the zero-field mobility of each of the six combinations of isotopically-pure, naturally-occurring Br − ions and Ne neutrals, starting from an ab initio interaction potential [15] that is highly accurate and is given at 38 ion-neutral separations between 2.27 and 11.34 bohr. Computer program PC [16] was used to calculate the transport cross sections from this potential with a precision of 0.04 % for collision energies from 10 −9 to 1.03 hartree.…”

“…With α = β = 0, these are the first approximation equations of the two-temperature (2T) theory [15], a kinetic theory that provides a means for calculating these correction factors, which are generally 0.10 or less.…”

“…(16) and (17) is that the correction factors, α and β, are functions of the ion-neutral interaction potentials as well as the ion and neutral masses. Since they are small, it is likely that the second approximation results for rigid-sphere interactions [15] can be used to approximate α and β in all orders of approximation for real interactions. Thus it will be assumed in this section that…”

Transport of O+ through argon gas

“…In recent works, [4][5][6][7] we have generated accurate ab initio interaction potentials and employed them to calculate transport, scattering, and spectroscopic properties. Where spectroscopic data were available, good agreement was obtained; however, this merely indicates that the interaction potential is reliable close to the energy minimum.…”

Gas-Phase Ion Chemistry of the Noble Gases: Recent Advances and Future Perspectives

“…This fragility is clearly appreciated, for example, by examining the properties of the diatomic X -•Ng (X -= F -, Cl -, Br -, I -, O -, S -), also extensively investigated with unceasing interest in the last decade. [157][158][159][160][161][162][163][164][165][166][167][168][169][170][171][172][173][174] The accurate theoretical data recently reported for the halide complexes are listed in Table 8.…”