Fragmentation of interstellar methanol by collisions with He˙⁺: an experimental and computational study

Abstract

Methanol is a key species in astrochemistry as its presence and reactivity provides a primary route to the synthesis of more complex interstellar organic molecules (iCOMs) that may eventually be...

The dawn of hydrogen and halogen bonds and their crucial role in collisional processes probing long-range intermolecular interactions

“…103 We also recall the experimental findings observed in reactivity of He + -polar molecule systems, investigated in a wide collision energy range including thermal and hyper-thermal conditions. [104][105][106] For recent examples of the influence of stereochemical effects on the reactivity of other ion-molecule systems at low and ultra-low collision energies, see, for instance, ref. 107-113.…”

“…103 We also recall the experimental findings observed in reactivity of He + -polar molecule systems, investigated in a wide collision energy range including thermal and hyper-thermal conditions. 104–106…”

The role of precursor states in the stereo-dynamics of elementary processes

“…[145][146][147][148][149] Moreover, molecular polarization can be also induced in a ''natural way'' within sufficiently high electric field gradients generated by strongly anisotropic intermolecular forces. [150][151][152][153][154][155][156] This phenomenon should emerge especially during collision events at low temperature, involving ions and molecules with pronounced permanent electric multi-pole, slowly rotating and flying at low speed.…”

“…3,6 -The selective role of the centrifugal barriers limits the orbital angular momentum components effectively promoting the reaction. In particular, such a role has been often invoked to describe some selectivity in ion-molecule reactions exploiting capture models, [145][146][147]149,[154][155][156] but in a more general vision, it is expected to control probability, structure and stability of the reaction precursor states, formed at low kinetic energy and under specific values of the orbital angular momentum of the collision complexes. Note also that a recent review suitably emphasizes some important limitations of the capture models when, in addition to the basic role of the long-range attraction, important short-range features of the interaction come into play.…”

Reactivity of the Ethenium Cation (C2H5+) with Ethyne (C2H2): A Combined Experimental and Theoretical Study

“…The significant under-observation with respect to the Langevin rate is unsurprising, as the model assumes that if the reactants have enough energy to surmount the centrifugal barrier, the reaction forms from the resultant ion-molecule complex with unit probability, with no accounting for any dissociation back to the reactants. Not only has this assumption been shown to be false in a number of previous studies [55,56,76], but the limitations of capture theories in providing quantitative assessments of reaction rates, especially for complex systems such as in the current study, have been explored extensively in literature [77]. 1 k tot is the total (i.e., summed over all the product channels) rate constant (in cm 3 •molecule −1 •s −1 ) at the specified average collision energy (E ave ), estimated as detailed in the text.…”