Matrix isolation model studies on the radiation-induced transformations of small molecules of astrochemical and atmospheric interest

Formation and Evolution of H2C3O+•Radical Cations: A Computational and Matrix Isolation Study

“…On the basis of such kinetic behavior, we had tentatively assigned the band in focus to some intermediate species (presumably cationic) arising directly from the C 2 H 2 ···CO complex . The idea that this unknown species might be a cation comes from the observation of the increased yield of C 2 H – in the C 2 H 2 /CO/Ar matrices (as compared to C 2 H 2 /Ar ones), while the yield of Ar 2 H + had not been evidently affected by the presence of CO. To note, the Ar 2 H + cations most probably originate from deprotonation of extremely acidic H 2 O +• radical cations (a small amount of water is a typical impurity in matrix-isolation experiments) …”

“…We may note that the studies of the radiation-induced evolution of complexes are particularly useful for modeling cold astrochemical processes occurring within the “building blocks” (recent examples may be found in refs and – ). Most probably, this evolution taking place both in matrices and in mixed ices − includes the formation of complex radical cations as intermediates; however, direct pieces of evidence on this hidden stage are quite limited due to the rapid recombination of primary cations with electrons or their secondary reactions. Thus, efforts should be made to elaborate the way to isolate and identify the primary ionic species resulting from the complexes.…”

Extraterrestrial prebiotic molecules: photochemistryvs.radiation chemistry of interstellar ices

“…29 Although not discussed in this review, matrix isolation studies, conducted under high vacuum rather than ultrahigh vacuum conditions, offer another method to study energetic processing of cosmic ice analogs. 30 A comprehensive understanding of radiation/photochemistry of condensed molecular films should include both (1) stimulated desorption studies of promptly generated fragments and (2) post-irradiation analysis of the complementary retained species. Electron/photon/ion stimulated desorption experiments typically involve quadrupole mass spectrometry (QMS) or time-of-flight mass spectrometry (ToF-MS).…”

Cationic Noble-Gas Hydrides: From Ion Sources to Outer Space

“…While the former process is probably hampered by the high barriers arising from the positive charges of the colliding partners, the PAHs route seems more plausible, especially in view of the predicted exothermic character of model reactions between NeH + and C 10 H 8 -Ng or C 32 H 14 -Ng (Ng = Ne, Ar) (Fortenberry, 2017). Other suggestions for conceivable formation routes come from studies performed in cold matrices (Feldman et al, 2016;Saenko and Feldman, 2016), showing that ionized molecules such as H 2 O and CH 3 OH (quite abundant in the outer space) might protonate Ng atoms so to eventually form the Ng-H-Ng + .…”