Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Fu-Ming Tao is active.

Publication


Featured researches published by Fu-Ming Tao.


Journal of Physical Chemistry A | 2012

Theoretical Study on the Structure and Stabilities of Molecular Clusters of Oxalic Acid with Water

Kevin H. Weber; Francisco J. Morales; Fu-Ming Tao

The importance of aerosols to humankind is well-known, playing an integral role in determining Earths climate and influencing human health. Despite this fact, much remains unknown about the initial events of nucleation. In this work, the molecular properties of common organic atmospheric pollutant oxalic acid and its gas phase interactions with water have been thoroughly examined. Local minima single-point energies for the monomer conformations were calculated at the B3LYP and MP2 level of theory with both 6-311++G(d,p) and aug-cc-pVDZ basis sets and are compared with previous works. Optimized geometries, relative energies, and free energy changes for the stable clusters of oxalic acid conformers with up to six waters were then obtained from B3LYP calculations with 6-31+G(d) and 6-311++G(d,p) basis sets. Initially, cooperative binding is predicted to be the most important factor in nucleation, but as the clusters grow, dipole cancellations are found to play a pivotal role. The clusters of oxalic acid hydrated purely with water tend to produce extremely stable and neutral core systems. Free energies of formation and atmospheric implications are discussed.


Chemical Physics Letters | 1999

Ionic dissociation of hydrogen bromide in water clusters: a computational study

Clinton Conley; Fu-Ming Tao

The ionic dissociation of hydrobromic acid in an aqueous environment is studied by density functional theory calculations on the water clusters HBr(H2O)n, n=1–4. The equilibrium structure, binding energies, vibrational frequencies, and dipole moments of the clusters are calculated in order to understand the mechanism of aqueous acid dissociation. These calculations indicate that HBr does not dissociate until at least three, preferably four, water molecules are positioned around the acid molecule. The Br–H bond grows progressively longer as more water molecules are added in the cluster, causing significant red-shift in its stretching frequency, along with drastic increase in the IR intensity.


Chemical Physics Letters | 1996

An accurate ab initio potential energy surface of HeH2O

Fu-Ming Tao; Zhiru Li; Yuh-Kang Pan

Abstract We present an accurate calculation of the intermolecular potential surface for the van der Waals complex HeH2O using complete fourth-order Moller-Plesset perturbation theory (MP4) with an efficient basis set containing bond functions. The calculation gives a global minimum at R=3.15 A , θ=105°, φ=0° (in a Jacobi coordinate system) with a minimum energy De=31.8 cm−1, along with barriers of 13.4 and 12.6 cm−1 for in-plane rotation at θ=0° and 180°, respectively, and a barrier of 20.0 cm−1 for out-of-plane rotation at θ=105°, φ=90°. The potential energy surface is compared with previously published surfaces for HeH2O, and with the potential energy surface for ArH2O.


Chemical Physics Letters | 1998

A density functional theory and ab initio study of the hydrolysis of dinitrogen pentoxide

Denise Hanway; Fu-Ming Tao

Abstract The density functional theory and ab initio methods are used to study two minimum energy pathways for the hydrolysis of N2O5 to form nitric acid, one involving a single water molecule and the other involving two water molecules. Both of the reactions are initiated by the nucleophilic attack on N2O5 by water while the additional water in the two-water reaction acts as a polar solvent to stabilize the ion pair resulted from the nucleophilic attack. The activation energy is 20 kcal/mol for the one-water reaction and it is reduced by half for the two-water reaction. The study suggests that the heterogeneous hydrolysis of N2O5 is likely more favorable than the homogeneous process.


Journal of Physical Chemistry A | 2014

Theoretical study on stable small clusters of oxalic acid with ammonia and water.

Kevin H. Weber; Qian Liu; Fu-Ming Tao

Thermodynamically stable small clusters of oxalic acid (CO2H)2, ammonia (NH3), and water (H2O) are studied through quantum chemical calculations. The (CO2H)2-NH3 core system with up to three waters of hydration was examined by B3LYP density functional theory and MP2 molecular orbital theory with the aug-cc-pVDZ basis set. The (CO2H)2-NH3 core complexes are observed to hydrogen bond strongly and should be found in appreciably significant concentrations in the atmosphere. Subsequent hydration of the (CO2H)2-NH3 core, however, is found to be somewhat prohibitive under ambient conditions. Relative populations of the examined clusters are predicted and the binding patterns detailed. Atmospheric implications related to new particle formations are discussed.


Chemical Physics Letters | 1998

PROTON TRANSFER REACTION OF HYDROGEN CHLORIDE WITH AMMONIA : IS IT POSSIBLE IN THE GAS PHASE?

Robert A. Cazar; Alan J. Jamka; Fu-Ming Tao

Abstract The mechanism of proton transfer between HCl and NH 3 and the effects of individual water molecules on the reaction are investigated by calculating the structures and energetics of a series of molecule clusters HCl–NH 3 –(H 2 O) n ( n = 0, 1, 2, 3) using high level ab initio theory. Without water, the system exists as a simple hydrogen-bonded complex and no proton transfer occurs from HCl to NH 3 . The first water molecule was found to induce a nearly flat potential energy pathway for proton transfer, but at least two water molecules must be involved for complete proton transfer from HCl to NH 3 . The study supports the likelihood of gas phase proton transfer in HCl–NH 3 in the presence of water vapor.


Chemical Physics Letters | 2003

Density functional study of structures and interaction hyperpolarizabilities of NH3–HCl–(H2O)n (n=0–4) clusters

Rujiao Li; Zhi-Ru Li; Di Wu; Xi-Yun Hao; Ying Li; Bing-Qiang Wang; Fu-Ming Tao; Chia-Chung Sun

Abstract The optimized structures of NH 3 –HCl–(H 2 O) n ( n =0–4) clusters have been obtained by B3LYP/d-aug-cc-pVDZ method. In the structure of n =1, proton transfer occurs. It is different from the results of some references. The first hyperpolarizabilities ( β 0 ) and some other properties of the clusters were calculated and the basis set effects were also studied. On the properties of the clusters, the β 0 value reduces with the increasing number of water molecules. For the subunits NH 3 –HCl, the β 0 value increases with the extent of proton transfer that result from an important solvent effects of water molecules.


Journal of Physical Chemistry A | 2014

Theoretical study of the hydrogen abstraction of substituted phenols by nitrogen dioxide as a source of HONO.

Abraham Shenghur; Kevin H. Weber; Nhan D. Nguyen; Watit Sontising; Fu-Ming Tao

The mild yet promiscuous reactions of nitrogen dioxide (NO2) and phenolic derivatives to produce nitrous acid (HONO) have been explored with density functional theory calculations. The reaction is found to occur via four distinct pathways with both proton coupled electron transfer (PCET) and hydrogen atom transfer (HAT) mechanisms available. While the parent reaction with phenol may not be significant in the gas phase, electron donating groups in the ortho and para positions facilitate the reduction of nitrogen dioxide by electronically stabilizing the product phenoxy radical. Hydrogen bonding groups in the ortho position may additionally stabilize the nascent resonantly stabilized radical product, thus enhancing the reaction. Catechol (ortho-hydroxy phenol) has a predicted overall free energy change ΔG(0) = -0.8 kcal mol(-1) and electronic activation energy Ea = 7.0 kcal mol(-1). Free amines at the ortho and para positions have ΔG(0) = -3.8 and -1.5 kcal mol(-1); Ea = 2.3 and 2.1 kcal mol(-1), respectively. The results indicate that the hydrogen abstraction reactions of these substituted phenols by NO2 are fast and spontaneous. Hammett constants produce a linear correlation with bond dissociation energy (BDE) demonstrating that the BDE is the main parameter controlling the dark abstraction reaction. The implications for atmospheric chemistry and ground-level nitrous acid production are discussed.


Chemical Physics Letters | 1999

Ab initio study of the intermolecular potential surface of He–NH3

Zhi-Ru Li; Arthur Chou; Fu-Ming Tao

Abstract The intermolecular potential surface for the van der Waals complex He–NH3 is studied by ab initio calculation using fourth-order Moller–Plesset perturbation theory (MP4) with a bond function basis set. The calculation gives a global minimum at R=3.26 A, θ=89°, φ=60° (in a Jacobi coordinate system) with a well depth of De=32.96 cm−1, along with barriers of 23.09 and 20.86 cm−1 for in-plane rotations at θ=0° and 180°, respectively, and a barrier of 10.45 cm−1 for out-of-plane rotation at θ=89°, φ=0°. The potential energy surface of He–NH3 is compared to those of Ar–NH3 and He–H2O, respectively.


Science China-chemistry | 2012

Theoretical study of mechanism and kinetics for the addition of hydroxyl radical to phenol

Pengzhen Wu; Jian Li; Shujin Li; Fu-Ming Tao

The reaction mechanism and kinetics for the addition of hydroxyl radical (OH) to phenol have been investigated using the hybrid density functional (B3LYP) method with the 6-311++G(2dp, 2df) basis set and the complete basis set (CBS) method using APNO basis sets, respectively. The equilibrium geometries, energies, and thermodynamics properties of all the stationary points along the addition reaction pathway are calculated. The rate constants and the branching ratios of each channel are evaluated using classical transition state theory (TST) in the temperature range of 210 to 360 K, to simulate temperatures in all parts of the troposphere. The ortho addition pathway is dominant and accounts for 99.8%–96.7% of the overall adduct products from 210 to 360 K. The calculated rate constants are in good agreement with existing experimental values. The addition reaction is irreversible.

Collaboration


Dive into the Fu-Ming Tao's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Arthur Chou

California State University

View shared research outputs
Top Co-Authors

Avatar

Kevin H. Weber

California State University

View shared research outputs
Top Co-Authors

Avatar

Lisa M. Visco

California State University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge