Gabriel Freitas - Academia.edu (original) (raw)
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Universitas Pembangunan Nasional "Veteran" Yogyakarta
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Papers by Gabriel Freitas
The Journal of Physical Chemistry A, 2015
This work reports CCSD(T)/aug-cc-pV(T+d)Z ab initio calculations for the lower energy region of t... more This work reports CCSD(T)/aug-cc-pV(T+d)Z ab initio calculations for the lower energy region of the ground electronic state of the HSO 2 system. Optimized geometries, total energies, zero-point vibrational energies, frequencies, complete basis set extrapolations, and reaction paths are reported at the same level of calculation. The connection of the two minima (synperiplanar HOSO and HSO 2) with the dissociation limit H + SO 2 through the van der Waals minimum H•••SO 2 was established. An important quantitative discrepancy with previous works is the fact that at the present level of calculation the energy difference between transition states connecting the global minimum synperiplanar HOSO to the HSO 2 minimum (TS 5) and to the van der Waals minimum H•••SO 2 (TS 6) is negligible, implying that the forward barriers after the synperiplanar HOSO global minimum have practically the same height. This result suggests that these two transition states may be involved in the path of the global minimum toward the exit channel H + SO 2. As a consequence, trajectories for the OH + SO collisions could evolve through the well formed by the HSO 2 minimum, therefore opening two competitive channels for the OH + SO → H + SO 2 reaction, a fact never reported in trajectory calculations.
The Journal of Physical Chemistry A, 2015
This work reports CCSD(T)/aug-cc-pV(T+d)Z ab initio calculations for the lower energy region of t... more This work reports CCSD(T)/aug-cc-pV(T+d)Z ab initio calculations for the lower energy region of the ground electronic state of the HSO 2 system. Optimized geometries, total energies, zero-point vibrational energies, frequencies, complete basis set extrapolations, and reaction paths are reported at the same level of calculation. The connection of the two minima (synperiplanar HOSO and HSO 2) with the dissociation limit H + SO 2 through the van der Waals minimum H•••SO 2 was established. An important quantitative discrepancy with previous works is the fact that at the present level of calculation the energy difference between transition states connecting the global minimum synperiplanar HOSO to the HSO 2 minimum (TS 5) and to the van der Waals minimum H•••SO 2 (TS 6) is negligible, implying that the forward barriers after the synperiplanar HOSO global minimum have practically the same height. This result suggests that these two transition states may be involved in the path of the global minimum toward the exit channel H + SO 2. As a consequence, trajectories for the OH + SO collisions could evolve through the well formed by the HSO 2 minimum, therefore opening two competitive channels for the OH + SO → H + SO 2 reaction, a fact never reported in trajectory calculations.