TY - JOUR
T1 - The selective role of long-range forces in the stereodynamics of ion–molecule reactions
T2 - the He++methyl formate case from guided-ion-beam experiments
AU - Cernuto, Andrea
AU - Pirani, Fernando
AU - Martini, Luca Matteo
AU - Tosi, Paolo
AU - Ascenzi, Daniela
PY - 2018/1/5
Y1 - 2018/1/5
N2 - Long-range intermolecular forces play a crucial role in controlling the outcome of ion–molecule chemical reactions, such as those determining the disappearance of organic or inorganic “complex” molecules recently detected in various regions of the interstellar medium due to collisions with abundant interstellar atomic ions (e.g. H+ and He+). Theoretical treatments, for example, based on simple capture models, are nowadays often adopted to evaluate the collision-energy dependence of reactive cross sections and the temperature dependent rate coefficients of many ion–molecule reactions. The obtained results are widely used for the modelling of phenomena occurring in different natural environments or technological applications such as astrophysical and laboratory plasmas. Herein it is demonstrated, through a combined experimental and theoretical investigation on a prototype ion–molecule reaction (He++methyl formate), that the dynamics, investigated in detail, shows some intriguing features that can lead to rate coefficients at odds with the expectations (e.g. Arrhenius versus anti-Arrhenius behaviour). Therefore, this study casts light on some new and general guidelines to be properly taken into account for a suitable evaluation of rate coefficients of ion–molecule reactions.
AB - Long-range intermolecular forces play a crucial role in controlling the outcome of ion–molecule chemical reactions, such as those determining the disappearance of organic or inorganic “complex” molecules recently detected in various regions of the interstellar medium due to collisions with abundant interstellar atomic ions (e.g. H+ and He+). Theoretical treatments, for example, based on simple capture models, are nowadays often adopted to evaluate the collision-energy dependence of reactive cross sections and the temperature dependent rate coefficients of many ion–molecule reactions. The obtained results are widely used for the modelling of phenomena occurring in different natural environments or technological applications such as astrophysical and laboratory plasmas. Herein it is demonstrated, through a combined experimental and theoretical investigation on a prototype ion–molecule reaction (He++methyl formate), that the dynamics, investigated in detail, shows some intriguing features that can lead to rate coefficients at odds with the expectations (e.g. Arrhenius versus anti-Arrhenius behaviour). Therefore, this study casts light on some new and general guidelines to be properly taken into account for a suitable evaluation of rate coefficients of ion–molecule reactions.
KW - astrochemistry
KW - charge transfer
KW - ion–molecule reactions
KW - mass spectrometry
KW - reaction mechanisms
UR - http://www.scopus.com/inward/record.url?scp=85038088463&partnerID=8YFLogxK
U2 - 10.1002/cphc.201701096
DO - 10.1002/cphc.201701096
M3 - Article
C2 - 29045020
AN - SCOPUS:85038088463
VL - 19
SP - 51
EP - 59
JO - ChemPhysChem
JF - ChemPhysChem
SN - 1439-4235
IS - 1
ER -