Kinetic and thermodynamic investigations on the HF elimination reactions from neutral and ionized CF3CH2F

Deciphering the irradiation induced fragmentation–rearrangement mechanisms in valence ionized CF3CH2F

“…20 Thermal energy and zero-point vibrational energy corrections have been incorporated into all energy results, which are expressed as enthalpies at 298.15 K. All geometry optimizations and vibrational frequency analyses were performed at the M06-2X 21 /cc-pVTZ 22 level of theory. As demonstrated in a previous study by our group, 17 this level is enough to obtain good quality geometries for fluoroalkanes and their corresponding cations.…”

“…[30][31][32] Atom-centered density matrix propagation (ADMP) [33][34][35][36] molecular dynamics simulations were performed for selected stationary points using the same level of theory as the geometry optimizations (M06-2X/cc-pVTZ). These primarily served to assess the HF rearrangement/elimination pathways, particularly focusing on the dynamic behavior of the ion-dipole structure [CF 2 CHF⋅ ⋅ ⋅HF] + , 17 which constitutes the global minimum energy structure with the formula C 2 H 2 F 4 + (see the supplementary material for more information). We also carried out ADMP calculations starting from TS1, the transition state linking CF 3 CH 2 F + to the ion-dipole complex [CF 2 CHF⋅ ⋅ ⋅HF] + (see Fig.…”

“…According to our previous HF elimination study, 17 reaction (2) demands a substantial energy input of 308.7 kcal/mol, or 13.39 eV, at 0 K. This energy requirement is significantly higher than any activation energy observed for neutral processes. On the other hand, it only slightly surpasses the energy needed to produce the first photofragments detected in threshold photoelectron spectroscopy experiments.…”

“…[2][3][4][5][6][7][8][9][10][11] With a few exceptions, 10,11 most of them focused on valence ionization (more details on other CF 3 CH 2 F irradiation experiments are given elsewhere 11 ). In the realm of computational studies centered on R-134a, a substantial body of research has also emerged, [12][13][14][15][16][17] the most recent of which is by our group. 17 There, we specifically examined the HF elimination from neutral and ionized R-134a and concluded that the most likely mechanism underpinning this reaction is a 2,1-HF elimination.…”

“…In the realm of computational studies centered on R-134a, a substantial body of research has also emerged, [12][13][14][15][16][17] the most recent of which is by our group. 17 There, we specifically examined the HF elimination from neutral and ionized R-134a and concluded that the most likely mechanism underpinning this reaction is a 2,1-HF elimination. This finding is consistent with the observations made for analogous HFCs, substantiated by both experimental and theoretical data.…”