A Quantum Study of the Chemical Formation of Cyano Anions in Inner Cores and Diffuse Regions of Interstellar Molecular Clouds

Formation ofCN−,C3N

“…The discovery of several carbon chain anions, C n N − (n = 1, 3, 5) and C n H − (n = 4,6,8) in the ISM has prompted a discussion about mechanism of their formation in the ISM [4][5][6][7]. Well before their discovery, the formation of molecular anions in the ISM was theorized by Herbst [8], who suggested that the anions could be formed in the ISM by radiative electronic attachment (REA).…”

“…However, for all carbon chain anions observed in the ISM the potential energy surfaces of the neutral molecule and the anion are almost parallel to each other, which implies that the electron capture cross section is small. One possibility in the process of REA that was not considered in this approach, is the role of weakly-bound dipole states of molecules with large dipole moments, such as C 5 N. Recently, it was suggested [5][6][7] that the weakly-bound dipole states might enhance the REA cross section, although no quantitative predictions have yet been made. A dipole state with a rotationally or vibrationally excited molecular core appears as a resonance in the electronic continuum spectrum and, therefore, can in principle enhance the REA cross section, at least, in some energy domains.…”

Forming NCO– in Dense Molecular Clouds: Possible Gas-Phase Chemical Paths From Quantum Calculations

“…The present study therefore intends to present a computational analysis of ion–molecule reactions that could lead to the formation of yet another molecular anion, the NCO – , a stable species exhibiting a closed-shell 1 Σ + ground electronic state, a large positive electron-affinity of 3.609 eV 10 and a permanent dipole moment of 1.5 D, 11 which is not far from what is called a “critical” value of ∼1.67 D. 9 The meaning of this comment will become clearer in the discussions of Section 3.…”

Optimal cloud use of quartic force fields: The first purely commercial cloud computing based study for rovibrational analysis of SiCH−

“…[22] However, the collisional dynamics and atomic silicon bonding preferences [23][24][25][26] of SiCH are likely to retain the additional electron in much the same way that another known interstellar anion, CN 2 , is believed to form collisionally in the ISM. [27][28][29] Hence, the detection or even nondetection of SiCH 2 in the ISM will provide more details about how anions may form in these environments. Furthermore, no siliconterminated alkyne chain molecules have been detected in the ISM even though there exists much speculation that they should be present therein.…”