Papers by Hue Thanh Nguyen
The Journal of Chemical Physics, 2012
We investigated the reactivity of O(1 D) towards two types of hydrogen atoms in CH 3 OH. The reac... more We investigated the reactivity of O(1 D) towards two types of hydrogen atoms in CH 3 OH. The reaction was initiated on irradiation of a flowing mixture of O 3 and CD 3 OH or CH 3 OD at 248 nm. Relative vibration-rotational populations of OH and OD (1 ≤ v ≤ 4) states were determined from their infrared emission recorded with a step-scan time-resolved Fourier-transform spectrometer. In O(1 D) + CD 3 OH, the rotational distribution of OD is nearly Boltzmann, whereas that of OH is bimodal; the product ratio [OH]/[OD] is 1.56 ± 0.36. In O(1 D) + CH 3 OD, the rotational distribution of OH is nearly Boltzmann, whereas that of OD is bimodal; the product ratio [OH]/[OD] is 0.59 ± 0.14. Quantum-chemical calculations of the potential energy and microcanonical rate coefficients of various channels indicate that the abstraction channels are unimportant and O(1 D) inserts into the C−H and O−H bonds of CH 3 OH to form HOCH 2 OH and CH 3 OOH, respectively. The observed three channels of OH are consistent with those produced via decomposition of the newly formed OH or the original OH moiety in HOCH 2 OH or decomposition of CH 3 OOH. The former decomposition channel of HOCH 2 OH produces vibrationally more excited OH because of incomplete intramolecular vibrational relaxation, and decomposition of CH 3 COOH produces OH with greater rotational excitation, likely due to a large torque angle during dissociation. The predicted [OH]/[OD] ratios are 1.31 and 0.61 for O(1 D) + CD 3 OH and CH 3 OD, respectively, at collision energy of 26 kJ mol −1 , in satisfactory agreement with the experimental results. These predicted product ratios vary weakly with collision energy.
Computational and Theoretical Chemistry, 2014
(CH 3) 3 Al (TMA) O 2 H 2 O and dimethylaluminum (DMA) DFT (B3LYP) (U)CCSD(T) Potential energy su... more (CH 3) 3 Al (TMA) O 2 H 2 O and dimethylaluminum (DMA) DFT (B3LYP) (U)CCSD(T) Potential energy surface a b s t r a c t (CH 3) 3 Al (TMA) has been employed for preparation of various thin films. It is also known to be hypergolic in the air. To unveil the hypergolic phenomenon, the mechanism for the reaction of TMA with O 2 and/or H 2 O molecules is studied using computational quantum methods. Our results show that TMA reacts with water much faster than with O 2 , and water is not an efficient catalyst to help O 2 reacting with TMA. The reactions of TMA with water and oxygen molecules can undergo subsequent ones in the air. However, the barrier predicted for production of CH 3 was found to be too high for combustion initiation under the ambient condition.
Catalysis Today, 2009
The effects of spin contamination errors in the optimized geometry of oxygen-adsorbed Au cluster ... more The effects of spin contamination errors in the optimized geometry of oxygen-adsorbed Au cluster model systems were examined by using broken symmetry geometry optimization (BS-opt) and an approximate spin-projected broken symmetry geometry optimization (AP-opt) method combined with the hybrid density functional (B3LYP) method. The AP-opt method effectively eliminated spin contamination errors from the BS-opt calculations of optimized geometry and energy of Aun–O2 (n=1, 2 and 13) model systems.
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Papers by Hue Thanh Nguyen