Structure of polyamidoamide dendrimers up to limiting generations : a mesoscale description (2009)
Maiti, Prabal K., Li, Youyong, Çağin, Tahir
The polyamidoamide (PAMAM) class of dendrimers was one of the first dendrimers synthesized by Tomalia and co-workers at Dow. Since its discovery the PAMAMs have stimulated many discussions on the...
Origin of static friction and its relationship to adhesion at the atomic scale (2007)
Zhang, Qing, Qi, Yue, Çağin, Tahir
Using atomic scale interfaces consisting of slabs of the same materials, we study the relationship between adhesion and static friction. The work of separation, which is a measure of adhesion, and...
Strong configurational dependence of elastic properties for a binary model metallic glass (2006)
Duan, Gang, Lind, Mary Laura, Demetriou, Marios D., Johnson, William L., Çağin, Tahir, ...
In this work, the strong dependence of elastic properties on configurational changes in a Cu–Zr binary metallic glass assessed by molecular dynamics simulations is reported. By directly evaluating...
The ferroelectric and cubic phases in BaTiO3 ferroelectrics are also antiferroelectric (2006)
Using quantum mechanics (QM, Density Functional Theory) we show that all four phases of barium titanate (BaTiO3) have local Ti distortions toward (an octahedral face). The stable rhombohedral phase...
The shear viscosity of liquid copper is studied using nonequilibrium molecular-dynamics simulations under planar shear flow conditions. We examined variation of viscosity as function of shear rate at...
Zhang, Qing, Qi, Yue, Çağin, Tahir
Kinetic friction during dry sliding along atomistic-scale Al(001)/Al(001) and alpha-Al2O3(0001)/alpha-Al2O3(0001) interfaces has been investigated using molecular dynamics (MD) with recently...
Duan, Gang, Xu, Donghua, Zhang, Qing, Zhang, Guoyun, Çağin, Tahir, Johnson, William L., ...
We have identified a binary bulk metallic glass forming alloy Cu46Zr54 by analyzing the structure and thermal behaviors of copper mold cast samples using x-ray diffraction, transmission electron...
Adhesion and nonwetting-wetting transition in the Al/alpha-Al2O3 interface (2004)
Zhang, Qing, Çağin, Tahir, Van Duin, Adri, Qi, Yue
Using a reactive force field (ReaxFF), we investigated the structural, energetic, and adhesion properties, of both solid and liquid Al/alpha-Al2O3 interfaces. The ReaxFF was developed solely with ab...
Atomistic simulations of kinks in 1/2a screw dislocations in bcc tantalum (2003)
Wang, Guofeng, Strachan, Alejandro, Çağin, Tahir
Two types of equilibrium core structures (denoted symmetric and asymmetric) for 1/2a screw dislocations in bcc metals have been found in atomistic simulations. In asymmetric (or polarized) cores, the...
Criteria for formation of metallic glasses: The role of atomic size ratio (2003)
Lee, Hyon-Jee, Çağin, Tahir, Johnson, William L.
We consider metallic alloys of Cu*, Cu, and Cu** in which the atoms differ only in their atomic radii and examine how the size ratio affects the local orders in the alloy systems. These studies use...
Luo, Sheng-Nian, Ahrens, Thomas J., Çağin, Tahir, Strachan, Alejandro, Swift, Damian C.
The maximum superheating and undercooling achievable at various heating (or cooling) rates were investigated based on classical nucleation theory and undercooling experiments, molecular dynamics (MD)...
Jang, Seung Soon, Çağin, Tahir
We have used molecular dynamics methods to investigate the effects of cyclic chain architecture on the properties of dilute solutions. In order to include solvent effects in estimating these...
Wang, Guofeng, Strachan, Alejandro, Çağin, Tahir
We use a family of embedded atom model potentials all based on accurate quantum-mechanical calculations to study the relation between Peierls stress and core properties of the 1/2a‹111› screw...
Friction anisotropy at Ni(100)/(100) interfaces: Molecular dynamics studies (2002)
Qi, Yue, Cheng, Yang-Tse, Çağin, Tahir
The friction of surfaces moving relative to each other must derive from the atomic interaction at interfaces. However, recent experiments bring into question the fundamental understanding of this...
Melting and crystallization in Ni nanoclusters: The mesoscale regime (2001)
Qi, Yue, Çağin, Tahir, Johnson, William L.
We studied melting and freezing of Ni nanoclusters with up to 8007 atoms (5.7 nm) using molecular dynamics with the quantum-Sutten–Chen many-body force field. We find a transition from cluster or...
Strachan, Alejandro, Çağin, Tahir
In answer to a Comment by Belonoshko [Phys. Rev. B 63, 096101 (2001)], we show that the B1-liquid melting curve of MgO obtained using two-phase simulations is in good agreement with the published one...
Critical behavior in spallation failure of metals (2001)
Strachan, Alejandro, Çağin, Tahir
Using molecular dynamics with an accurate many-body potential, we studied the rapid expansion of Ta metal following the high compression (50 to 100 GPa) induced by high velocity (2 to 4 km/s) impact....
Thermal conductivity of diamond and related materials from molecular dynamics simulations (2000)
Che, Jianwei, Çağin, Tahir, Deng, Weiqiao
Based on the Green–Kubo relation from linear response theory, we calculated the thermal current autocorrelation functions from classical molecular dynamics (MD) simulations. We examined the role of...
QM(DFT) and MD studies on formation mechanisms of C60 fullerenes (2000)
Hua, Xinlei, Çağin, Tahir, Che, Jianwei
One of the most puzzling aspects of fullerenes is how such complicated symmetric molecules are formed from a gas of atomic carbons, namely, the atomistic or chemical mechanisms. Are the atoms added...
Thermal conductivity of carbon nanotubes (2000)
As the sizes of electronic and mechanical devices are decreased to the micron and nanometre level, it becomes particularly important to predict the thermal transport properties of the components....
Molecular modelling of dendrimers for nanoscale applications (2000)
Çağin, Tahir, Wang, Guofeng, Martin, Ryan, Breen, Nicholas
Dendrimers are well defined, highly branched macromolecules that radiate from a central core and are synthesized through a stepwise, repetitive reaction sequence that guarantees complete shells for...
Phase diagram of MgO from density-functional theory and molecular-dynamics simulations (1999)
Strachan, Alejandro, Çağin, Tahir
We use first-principles methods (no empirical parameters) to establish the phase diagram for the B1(NaCl), B2(CsCl), and liquid phases of MgO. We used density-functional theory with the generalized...
Studies of fullerenes and carbon nanotubes by an extended bond order potential (1999)
We present a novel approach to combine bond order potentials with long-range nonbond interactions. This extended bond order potential consistently takes into account bond terms and nonbond terms. It...
Çağin, Tahir, Che, Jianwei, Gardos, Michael N., Fijany, Amir
To date most of the microelectromechanical system (MEMS) devices have been based on silicon. This is due to the technological know-how accumulated on the manipulation, machining and manufacturing of...
Strain Rate Induced Amorphization in Metallic Nanowires (1999)
Ikeda, Hideyuki, Qi, Yue, Çağin, Tahir, Samwer, Konrad, Johnson, William L.
Using molecular dynamics simulations with a many-body force field, we studied the deformation of single crystal Ni and NiCu random alloy nanowires subjected to uniform strain rates but kept at 300 K....
To predict phase transitions in ceramics and minerals from molecular dynamics simulations, we have developed a force field in which the charges are allowed to readjust instantaneously to the atomic...
Qi, Yue, Çağin, Tahir, Kimura, Yoshitaka
We used molecular dynamics (MD) to obtain an atomistic description of the melting, glass formation, and crystallization processes in metal alloys. These studies use the quantum Sutton-Chen many-body...
Thermal and mechanical properties of some fcc transition metals (1999)
Çağin, Tahir, Dereli, G., Uludogan, M., Tomak, M.
The temperature dependence of thermodynamic and mechanical properties of six fcc transition metals (Ni, Cu, Ag, Au, Pt, Rh) are studied using molecular dynamics (MD) simulations. The structures are...
In this paper, we present extensive molecular mechanics and molecular dynamics studies on the energy, structure, mechanical and vibrational properties of single-wall carbon nanotubes. In our study we...
Position of K atoms in doped single-walled carbon nanotube crystals (1998)
Recent experiments by Lee et al. [Nature (London) 363, 255 (1997)] show that doping carbon single-wall nanotube (SWNT) ropes with K, Rb, or Br2 leads to metallic conductivity, but the structure and...
Wetting of crystalline polymer surfaces: A molecular dynamics simulation (1995)
Molecular dynamics has been used to study the wetting of model polymer surfaces, the crystal surfaces of polyethylene (PE), poly(tetrafluoroethylene) (PTFE), and poly(ethylene terephthalate) (PET) by...
Melting of a repulsive screened Coulomb system in two dimensions: Effect of corrugation (1992)
Seong, Hyangsuk, Mahanti, S. D., Sen, Surajit, Çağin, Tahir
By use of constant energy molecular dynamics simulations, we have investigated the melting and freezing transitions in a two-dimensional system consisting of a constant density of classical particles...
Domains and domain walls in graphite intercalation compounds (1992)
Seong, Hyangsuk, Sen, Surajit, Çağin, Tahir, Mahanti, S. D.
The structure of domains and domain walls in the low-temperature solid phase of stage-2 alkali-metal graphite intercalation compounds is studied using molecular-dynamics (MD) simulation and a model...
Dynamic simulations of water at constant chemical potential (1992)
Ji, Jie, Çağin, Tahir, Pettitt, B. Montgomery
The grand molecular dynamics (GMD) method has been extended and applied to examine the density dependence of the chemical potential of a three-site water model. The method couples a classical system...
Isothermal molecular-dynamics ensembles (1988)
S. Nosé [Mol. Phys. 52, 255 (1984); J. Chem. Phys. 81, 511 (1984)] has developed a form of molecular dynamics that generates the canonical ensemble. Since molecular-dynamics calculations are carried...
Elastic constants of sodium from molecular dynamics (1988)
We have performed molecular-dynamics calculations of the adiabatic elastic constants of sodium at three different temperatures, T=198, 299, and 349 K. Our method uses fluctuation formulas appropriate...
Fundamental treatment of molecular-dynamics ensembles (1988)
In microcanonical molecular dynamics the conservation of total momentum implies that the trajectories generate an ensemble with constant total momentum. We present the exact statistical mechanics of...