Dr. Duan is a pioneer in the integration of the principles and knowledge of molecular dynamics, statistical mechanics, ab initio simulations, and thermodynamics to geochemical problems. He devoted all his effort to bridging the gap between physicochemical knowledge and the study of geochemical systems, as evidenced by his many papers shown in the attached references, which have been extensively cited by scientists from over forty countries. His major scientific contributions are:
1.         Established a series of excellent thermodynamic models of geological fluids, which was published in thirty-one peer-reviewed papers. These models have been extensively cited or used by scientists from over forty countries, in their studies of fluid-inclusions, CO₂ sequestration, methane hydrate formation, fluid-rock interaction, gas exploration, and experimental calibrations. These models not only can reproduce about 60,000 evaluated experimental data points (PVT, phase equilibrium, enthalpy, solubility, homogenization, etc.) from over 100 laboratories, but also can be used to extrapolate to the P-T conditions well beyond the experimental P-T range, such that they increase substantially the applicability of the experimental results that they were based on. Also, many extrapolations based on these models have been proved by later experiments. These models have been cited more than 800 times in international journals and have been used by over 1000 scientists world-wide, as shown in www.isiknowledge.com. Most of these models have been programmed and online calculations have been made available at www.geochem-model.org, which has been used preferably by many scientists among available models.
2.         Prof. Zhenhao Duan Pioneered the work on computational geochemistry by integrating the principles and methods of molecular dynamics, ab initio simulation, statistical mechanics, and thermodynamics. Integration of the physicochemical methods for geochemical studies becomes increasingly useful in dealing with problems that are difficult to solve by experiments, especially under extreme conditions. For example, many experiments have been performed for geological fluids, but they are generally limited to conditions less than a few thousand atmospheres. Using the ab initio potential force, Dr. Duan successfully simulated fluid properties up to 100,000 atm. He also successfully simulated phase equilibria and fluid structure, and predicted the formation conditions of methane hydrates. His work was highly appreciated by peers and was considered to be, for example, “a triumph in computational geochemistry”, as commented by Dr. David Wesolowski, Associate Editor of Geochimica et Cosmochimica Acta.
3.         Applied his and co-workers’ models in many geochemical applications, such as methane hydrate formation, geothermal energy, mantle fluid composition, and others, as shown in Part III of the attached reference list.

1.Thermodynamic, molecular physics of C-H-O-S fluids in the Earth,
2.Deep carbon cycle
3.Thermodynamics of gas-water-salt systems
4.Interplay between geochemistry and modern physical chemistry

Part I: Thermodynamic Modeling of Geological Fluids
1.    Zhenhao  Duan, N. Moller and J. H. Weare. (1992a), An equation of state (EOS) for CH₄-CO₂-H₂O   I: pure systems from 0 to 1000  ^oC and from 0 to 8000 bar. Geochim. Cosmochim. Acta , v56, pp. 2605-2617
2.    Zhenhao  Duan, N. Moller and J. H. Weare (1992b), An equation of state (EOS) for CH₄ CO₂-H₂O   II: Mixtures from 0 to 100  ^oC and from 0 to 1000 bar. Geochim. Cosmochim. Acta, v56, pp. 2619-2631
3.    Zhenhao  Duan, N. Moller, J. Greenberg and J. H. Weare (1992c), Prediction of methane solubilities in natural waters to high ionic strength from 0 to 250  ^oC and from 0 to 1600 bar. Geochim. Cosmochim. Acta, v56, pp.1451-1460
4.    Zhenhao  Duan, N. Moller and J. H. Weare (1992d) Molecular dynamics simulation of PVT properties of geological fluids and a equation of state of nonpolar and weakly polar gases up to 2000 K and 20,000 bar.  Geochim. Cosmochim. Acta, v56, pp3839-3845
5.    Zhenhao  Duan, N. Moller and J. H. Weare (1995a), Measurements of the PVT properties of water to 25 kbars and 1600oC  from synthetic fluid inclusions in Corundum.   Geochim. Cosmochim. Acta, v59, pp. 2693
6.    Zhenhao  Duan, N. Moller and J. H. Weare ( 1995b), Equation of state for the NaCl-H₂O-CO₂ system: prediction of phase equilibria and volumetric properties.   Geochim. Cosmochim. Acta, v59, pp. 2869-2882
7.    Zhenhao  Duan, N. Moller and J. H. Weare ( 1996a), a general equation of state for supercritical fluids and molecular dynamics simulation of . Geochim. Cosmochim. Acta, v60, pp. 1209-1216
8.    7. Zhenhao  Duan, N. Moller and J. H. Weare (1996b), Equation of state for the NH₃-H₂O system,   J. Solu. Chem. v25 pp. 43-50
9.    Zhenhao  Duan, N. Moller and J. H. Weare (1996c), Prediction of the solubility of  H₂S  in the NaCl aqueous solutions. Chemical Geology. v130, pp.15-20
10.   Zhenhao  Duan, N. Moller and J. H. Weare (1995a), Measurements of the PVT properties of water to 25 kbars and 1600^oC  from synthetic fluid inclusions in Corundum.   Geochim. Cosmochim. Acta, v59, pp. 2693
11.   Zhenhao  Duan, N. Moller and J. H. Weare ( 1995b), Equation of state for the NaCl-H₂O-CO₂ system: prediction of phase equilibria and volumetric properties.   Geochim. Cosmochim. Acta, v59, pp. 2869-2882
12.   Zhenhao Duan, N. Moller and John H. Weare (2003a) Equation of state for the H₂O-CO₂-CH₄-NaCl system: phase equilibria and volumetric properties. Geochim. Cosmochim. Acta  v67, pp 671-680.
13.   Zhenhao Duan and Rui Sun (2003) An improved model calculating CO₂ solubility in pure water and aqueous NaCl solutions from 273 to 533 K and from 0 to 2000 bar. Chem. Geol., v193, pp 253-271
14.  Rui Sun,  Zhengfang Huang,  Zhenhao Duan, (2003) A new equation of state and Fortran 77 program to calculate vapor-liquid phase equilibria of the CH₄-H₂O system at low temperatures,
15.   Zhenhao Duan and Jiawen Hu (2004) A New Cubic Equation of State and Its Applications to the Modeling of vapor-liquid Equilibria and volumetric properties, Geochim. Cosmochim. Acta vol. 68, pp. 2997-3009
16.   Jiawen Hu, Hui’an Yin, Zhenhao Duan (2004), A new general method for the derivation of the closed in the phase diagram space of multisystems:(I) the direct method, Journal of Metamorphic Geology, v22,  pp 413-426
17.   Jiawen Hu and Zhenhao Duan (2005) Theoretical prediction of the coordination number, local composition, and pressure-volume-temperature properties of square-well and square-shoulder fluids. J. Chem. Phys., v123, 244505.     
18.   Shide Mao, Zhigang Zhang, Jiawen Hu and Zhenhao Duan (2005) An accurate model for calculating C₂H₆ solubility in pure water and aqueous NaCl solutions. Fluid Phase Equilibia v238, 77-86.
19.   Shide Mao and Zhenhao Duan (2006) A thermodynamic model for calculating nitrogen solubility, gas phase composition and density of the H2O-N2-NaCl system. Fluid Phase Equilibria., v248, 103-114.
20.   Zhenhao Duan, John H. Weare J. and Nancy Moller (2006a) A high temperature equation of state for the H₂O-CaCl₂ and H₂O-MgCl₂ systems. Geochim. Cosmochim. Acta, v70, 3765-3777.
21.   Zhenhao Duan and Rui Sun  (2006b) A model to predict phase equilibrium of CH₄ and CO₂ clathrate hydrate in aqueous electrolyte solutions. Amer. Mineral., v91, 1346-1354.
22.   Zhenhao Duan and Shide Mao (2006c) A thermodynamic model for calculating methane solubility, density and gas phase composition of methane-bearing aqueous fluids from 273 to 523 K and from 1 to 2000 bar. Geochim. Cosmochim. Acta., v70, 3369-3386.
23.   Zhenhao Duan , Rui Sun R, Chen Zhu and I-Ming Chou (2006d) An improved model for the calculation of CO₂ solubility in aqueous solutions containing Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, and SO₄^2-. Marine Chem., v98, 131-139.
24.   Li DD, and Zhenhao Duan (2007) The speciation equilibrium coupling with phase equilibrium in the H₂O-CO₂-NaCl system from 0 to 250 °C, from 0 to 1000 bar and from 0 to 5 molality of NaCl. Chemical Geology., 244 (3-4): 730-751.
25.   Zhenhao Duan, Sun R, Liu R, and Zhu C, (2007a) An accurate thermodynamic model for the calculation of H2S solubility in pure water and brines. Energy & Fuels., 21(4) 2056-2065
26.   Hu JW, Zhenhao Duan, Zhu C, and Chou IM, (2007) PVTx properties of the CO₂-H₂O and CO₂-H₂O-NaCl systems below 647 K: Assessment of experimental data and thermodynamic models. Chemical Geology., 238 (3-4): 249-267.
27.   Zhenhao Duan , Dedong Li (2008a) Coupled phase and aqueous species equilibrium of the H₂O–CO₂–NaCl–CaCO₃ system from 0 to 250 C, 1 to 1000 bar with NaCl concentrations up to saturation of halite.Geochim. Cosmochim. Acta, 72 (20): 5128-5145.
28.   Zhenhao Duan, Hu JW, Li DD and MAO SD (2008b), The Density of the CO₂-H₂O and CO₂-H₂O-NaCl Systems Up to 647 K and 100 Mpa, Energy & Fuels, in press
29.   Qin JF, Rosenbaurer B. and Zhenhao Duan (2008), Experimental Measurements of Vapor-Liquid Equilibria of the  H₂O + CO₂ + CH₄ Ternary System, J. CHEM. ENG. DATA, in press
30.   MAO SD and Zhenhao Duan (2008)The PVTx properties of binary aqueous chloride solutions up to 573 K and 1000 bar, J CHEM. THERMODYNAMICS, 40 (7): 1046-1063.
31.   Shide Mao, Zhenhao Duan and Wenxuan Hu(2009) A vapor–liquid phase equilibrium model for binary CO₂–H₂O and CH₄–H₂O systems above 523K for application to fluid inclusions.The Journal of Supercritical Fluids, 50 (2009): 13-21.
Most of the above models have been programmed and online calculation has been made available online: www.geochem-model.org
 

Part II: Molecular level simulation of geological fluids and minerals
1.    Zhenhao  Duan, N. Moller and J. H. Weare (1992d) Molecular dynamics simulation of PVT properties of geological fluids and a equation of state of nonpolar and weakly polar gases up to 2000 K and 20,000 bar.  Geochim. Cosmochim. Acta, v56, pp3839-3845
2.    Zhenhao  Duan, N. Moller and J. H. Weare. (1995c), Molecular dynamics simulation of water Properties using RWK2 potential: From clusters to bulk water.  Geochim. Cosmochim. Acta, v59. pp. 3345-3357
3.    Zhenhao  Duan, N. Moller and J. H. Weare. (1995d), Molecular dynamics equation of state for non-polar geochemical fluids.  Geochim. Cosmochim. Acta, v56, pp.1533-1538
4.    Zhigang Zhang and Zhenhao Duan (2002) Phase equilibria of the system methane-ethane from temperature scaling Gibbs Ensemble Monte Carlo simulation. Geochim. Cosmochim. Acta, v66, pp 3431-3439
5.    Zhenhao Duan and Zhigang Zhang (2003b) Solvation properties of Li⁺ and Cl^- in water: molecular dynamics simulation with a non-rigid model, Molecular Physics, v101, pp1501-1510
6.    Zhenhao Duan, Nancy Moller, John Weare (2004a) Gibbs Ensemble Simulation of phase equilibria with a non-rigid model, Journal of Physical Chemistry B, v108, 20303-20309
7.    Zhigang Zhang and Zhenhao Duan (2004) Lithium chloride ionic association in dilute aqueous solution: a constrained molecular dynamics study. Chemical Physics, v297, pp 221-233
8.    Zhigang Zhang and ZhenhaoDuan (2005) An optimized molecular potential for carbon dioxide. J. Chem. Phys., v122, 214507.
9.    Zhigang Zhang and ZhenhaoDuan (2005) Prediction of the PVT properties of water over wide range of temperatures and pressures from molecular dynamics simulation. Phys. Earth Planetary Interiors, v149, 335-354.     
10.   Zhenhao Duan and Zhigang Zhang (2006d) Equation of state of the H₂O-CO₂ system up to 10 GPa and 2573K: Molecular dynamics simulations with ab initio potential surface. Geochim. Cosmochim. Acta., v70, 2311-2324.
11.   Zhang C, Zhenhao Duan, and Zhang ZG. (2007b) Molecular dynamics simulation of the CH4 and CH4-H2O systems up to 10 GPa and 2573 K. Geochim. Cosmochim. Acta, 71 (8): 2036-2055.
12.   Hu JW, Zhenhao Duan, Shi XL, and Zhu J, (2007) A general local composition and coordination number model for square-well fluids with variable well width and diameter ratio. Molecular Physics., 105（8），1019-1037
13.   Mingyan Li, Zhenhao Duan, Zhigang Zhang,Chi Zhang & John Weare (2008) The structure, dynamics and solvation mechanisms of ions in water from long time molecular dynamics simulations: a case study of CaCl₂ (aq) aqueous solutions.Molecular Physics, 106 (24): 2685-2697
 

Part III:  Geochemical Applications:
1.         Zhenhao  Duan, N. Moller, T. DeRocher and J. H. Weare(1996d), Prediction of boiling, scaling and formation condition in geothermal reservoir: application of computer programs TEQUIL and GEOFLUIDS. Geothermics  1996, v25, pp.663-678
2.         Duan ZH, N. Moller, J. Greenberg and J. H. Weare Models of geothermal brine chemistry for optimizing resource performance. Proceedings of Geothermal Program review IX, 1991.
3.         John Weare, Zhenhao  Duan and N. Moller.1998, Modeling hydrothermal solutions to high  temperatures and  pressures (a chapter of a book titled "Geological fluids").
4.         Zhenhao Duan and W. Hu (2001) The accumulation of potash in a continental basin: The  example of Qarhan Saline Lake, West China, Europ. J. Mineral., v13, pp1223-1233
5.         Rui Sun and Zhenhao Duan (2005) Prediction of CH₄ and CO₂ hydrate phase equilibrium and cage occupancy from ab initio intermolecular potentials. Geochim. Cosmochim. Acta, v69,  4411-4424.    
6.         Sun R, and Zhenhao Duan, (2007) An Accurate Model to predict the Thermodynamic Stability of Methane Hydrate and Methane Solubility in Marine Environments. Chemical Geology., 244 (1-2): 248-262.
7.         Chi Zhang and Zhenhao Duan. (2009) A model for C–O–H fluid in the Earth’s mantle . Geochimica et Cosmochimica Acta., 73 (7): 2089-2102.