Structure, Ionization, and Fragmentation of Neutral and Positively Charged Hydrogenated Carbon Clusters: C_nH_m^q+ (n = 1–5, m = 1–4, q = 0–3)

Abstract

In this work we present a systematic theoretical study of neutral and positively charged hydrogenated carbon clusters (C(n)H(m)(q+) with n = 1–5, m = 1–4, and q = 0–3). A large number of isomers and spin states (1490 in total) was investigated. For all of them, we optimized the geometry and computed the vibrational frequencies at the B3LYP/6-311++G(3df,2dp) level of theory; more accurate values of the electronic energy were obtained at the CCSD(T)/6-311++G(3df,2dp) level over the geometry previously obtained. From these simulations we evaluated several properties such as relative energies between isomers, adiabatic and vertical ionization potentials, and dissociation energies of several fragmentation channels. A new analysis technique is proposed to evaluate a large number of fragmentation channels in a wide energy range.

Breakdown curves of CH2(+), CH3(+), and CH4(+) molecules

“…where IP is the adiabatic ionization potential of the corresponding species. Table 4 reports on the ionization potentials used in the calculations taken from Sanchez et al (2016). With these internal energies and the CH + y BDC's (see Figs.…”

“…Semi-empirical BDCs of CH (+) y have been recently constructed using the experimental results (dissociation BR and kinetic energy release) of the high velocity collision between CH (+) y beam and He target (IdBarkach et al (2019) referred to as Paper I in the following). Detailed structure calculations for CH (+) y were also used for this purpose (Sanchez et al 2016). In the same paper in which BDCs were constructed, predictions of photo-dissociation BR's for different UV flux were performed.…”

Eliminating symmetry problems in electronegativity equalization and correcting self‐interaction errors in conceptual DFT

“…The energy difference between XY and XY + is obtained from (i) theoretical calculations, for example, Refs. [] (ii) molecular photoelectron (PE) spectra, for example, Refs. [] The PE spectra are often assigned to the electron removal from a particular bond, b , for example, Refs.…”

“…The updated I and A data are listed in Supporting Information Table S, for their references, see Refs. [].…”

“…We investigate molecules with up to four equivalent bonds, such as CO 2 , H 2 O, CH 3 , SiH 3 , NH 3 , CX 4 (X = H, F, Cl, Br), SiH 4 and molecules characterized by non‐equivalent bonds, for example , HCN, COS, CH 3 I, C 2 H 2 , C 2 H 4 , C 2 H 6 , and H 2 C = O (Table ) and Supporting Information (Table S1). Several polyatomic electron affinities have been revised and differ significantly from the values used earlier . Due to some exaggeratedly negative A 0, v values in Refs.…”