A new publication of researchers Tam V.-T. Mai, Minh v. Duong, Hieu T. Nguyen and Lam K. Huynh was supported by fund based on Clause 1, Article 14 of Decision No. 03/ QD-KHCNTT dated January 2^nd, 2018 about promulgating the Internal Spending Rules of the Institute for Computational Science and Technology, which stipulates support for International and domestic publication. Here is an introduction to the publication of the researchers.
 
Publication of research “Ab initio Kinetics of the HOSO₂ + ³O₂ → SO₃ + HO₂ Reaction”
 
On January 31^st, 2018, researcher of Molecular Science Lab at ICST (Tam V.-T. Mai), and his colleagues, Minh v. Duong, Hieu T. Nguyen and Lam K. Huynh have just published a research named “Ab initio Kinetics of the HOSO₂ + ³O₂ → SO₃ + HO₂ Reaction” on “The Journal of Physical Chemistry Chemical Physics”
 
The detailed kinetic mechanism of HOSO₂ + ³O₂ reaction, which plays a pivotal role in the atmospheric oxidation of SO₂, was investigated using accurate electronic structure calculations and novel statistical thermodynamic/kinetic models. Explored at the accurate composite method W1U, the detailed potential energy surface (PES) revealed that the addition of O₂ to HOSO₂ radical to form the adduct (HOSO₄) proceeds via a transition state with a slightly positive barrier (i.e., 0.7 kcal/mol at 0 K). Such a finding compromises a long-term hypothesis about this channel of being a barrierless process. Moreover, the overall reaction was found slightly exothermic by 1.7 kcal/mol at 0 K, which is in good agreement with recent studies. On the newly-constructed PES, the temperature- and pressure-dependent behaviors of the title reaction were characterized in a wide range of conditions (T = 200 – 1000 K & P = 10 – 760 torr) using the integrated deterministic and stochastic master equation/Rice–Ramsperger–Kassel–Marcus (ME/RRKM) rate model in which corrections for hindered internal rotation (HIR) and tunneling treatments were included. The calculated numbers were found to be in excellent agreement with literature data. The sensitivity analyses on the derived rate coefficients with respect to the ab initio input parameters (i.e., barrier height and energy transfer) were also performed to further understand the kinetic behaviors of the title reaction. The detailed kinetic mechanism, consisting of thermodynamic and kinetic data (in NASA polynomial and modified Arrhenius formats, respectively), was also provided at different T & P for further use of modeling/simulation of any related systems.
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Fig. 7. Comparison between calculated and literature rate coefficients as a function of temperature at different pressures for HOSO2 + 3O2 - SO3 + HO2. Literature data are from the work of Margitan¹⁴ (‘‘Expt. (Martigan  984, P = 40–100 Torr)’’); Martin and coworkers⁴⁹ (‘‘Expt. (Martin 1986, P = 1–6.4 Torr)’’); Gleason and coworkers^47,48 (‘‘Expt. (Gleason 1987, P = 4–8.3 Torr) & (Gleason 1988, P = 47–64 Torr)’’); DeMore and coworkers¹¹³ (‘‘Review (DeMore 1997)’’) and Atkinson and coworkers¹¹⁴ (‘‘Review (Atkinson 2004)’’).
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