Q2. What is the simplest explanation for the recombination of C3N?
Mutual anion-cation neutralization of C3N− with positive daughter ions of HC3N, a process which would depend on cyanoacetylene density, can also be ruled out because positive ion counts remain low.
Q3. Why was the reaction expected to be of significance for the early phase of the anion growth sequence?
Because of the possible existence of an ion product channel, the reaction was expected to be of significance for the early phase of the anion growth sequence.
Q4. What is the important part of the Monte-Carlo algorithm?
In order to estimate the uncertainty associated with the results, the authors perform Monte-Carlo simulations in which several surrogate datasets are generated in order to mimic experimental errors (determination of the mass peak maxima at fast mass scanning rates) and/or fluctuations (mass flows, pressures, ...).
Q5. Why was the rate coefficient expected to be fast?
Because of the polar nature of HC3N, the rate coefficient was then expected to be fast as it depends strongly on the dipole moment μ.
Q6. What is the efficient route for ion growth?
Even if polyatomic neutrals with low frequency modes are the most efficient detachers (such as cyanoacetylene), this route remains slow compared to e.g. charge transfer reactions.
Q7. What is the nature of the neutral products of this second exit channel?
A minor exit channel, reactive detachment (< 9%), has also been uncovered, although the nature of the neutral products of this second exit channel has not been identified yet.
Q8. Why is the proton transfer expected to occur rapidly?
On the basis of these theoretical results, the authors expect the proton transfer to occur rapidly because its corresponding barrier is low compared to the significant internal energy of the complex.
Q9. What is the way to minimize 2?
To minimize χ2, the authors select a Nelder-Mead simplex algorithm used to find the minimum of unconstrained multi-variable function using derivative-free method starting with an initial estimate (Nelder and Mead, 1965).
Q10. What is the ion product in the mass spectra?
mass spectra show that the secondary ion C143 N − (m/z = 50) reacts with HC3N, although no ion product is detected for this process.
Q11. What is the ideal situation for the temperature dependence?
this ideal situation corresponds to an asymptotical upper limit value when the temperature reaches zero with a temperature dependence in T−1/2.
Q12. At what altitudes is the reaction of CxH with HCN supposed to contribute?
At altitudes below 800 km, the reaction of CxH− with HCN is supposed to contribute at the same level to the generation of this small anion.