Quantum effects in the capture of charged particles by dipolar polarizable symmetric top molecules. II. Interplay between electrostatic and gyroscopic interactions

Abstract

Within the general axially nonadiabatic channel approach described in Paper I of this series [M. Auzinsh, E. I. Dashevskaya, I. Litvin, E. E. Nikitin, and J. Troe, J. Chem. Phys. 139, 084311 (2013)], the present article analyzes the simultaneous manifestation of electrostatic and gyroscopic interactions in the quantum capture of dipolar polarizable symmetric top molecules by ions. As a demonstration, the rate coefficients for capture of CH 3 D and CD 3 H by H + , D + , and H 3 + are calculated.

Multipole-moment effects in ion–molecule reactions at low temperatures: part I – ion-dipole enhancement of the rate coefficients of the He+ + NH3 and He+ + ND3 reactions at collisional energies Ecoll/kB near 0 K

“…The experimental observations are analysed in the realm of an adiabatic capture model inspired by the earlier theoretical work of Clary and co-workers 3,5,16 and Troe and coworkers. 4,6,[17][18][19][20] Because the existence or non-existence of a given n mp -pole moment is dictated by the molecular symmetry, the interpretation of the experimental observations requires consideration of the corresponding molecular-symmetry groups, in particular when determining the nuclear-spin symmetries and occupations of the rotational quantum states of the neutral molecules. We follow here earlier treatments, in particular those presented in ref.…”

“…where DE coll /k B is the FWHM of a Gaussian function. In eqn (19), DT res is an effective experimental temperature corresponding to the distribution of relative velocities of the He(n) atoms and the ammonia molecules at zero nominal collisional energy (i.e., when v Ryd À v GS c = 0). The value of DT res is mostly determined by the temperature of the Rydberg-atom cloud released from the quadrupole trap.…”

The H2+ + HD reaction at low collision energies: H3+/H2D+ branching ratio and product-kinetic-energy distributions

“…However, below 10 K, ion-molecule reactions have been predicted to exhibit strong effects caused by the alignment of the rotational angular momentum vector of apolar neutral molecules and the orientation of polar neutral molecules in the Coulomb field of the ion, see, e.g., ref. [13][14][15][16][17][18][19][20][21][22][23][24][25]. These effects tend to be strongly dependent on the rotational state of the neutral molecule but have not been systematically studied experimentally yet below 10 K.…”

Deviation of the rate of the reaction from Langevin behaviour below 1 K, branching ratios for the and product channels, and product-kinetic-energy distributions

“…Examples involving the theoretical description of fast, barrier-free ion-molecule reactions relevant for the present investigation include Refs. [17][18][19][20][21][22][23][24][25][26].…”