Victor Milman | Dassault systemes (original) (raw)
Papers by Victor Milman
Physical review letters, Jan 5, 1993
Progress in Materials Science, 1994
Zeitschrift für Kristallographie – Crystalline Materials, 2014
Density functional theory based calculations are commonly employed to complement experimental hig... more Density functional theory based calculations are commonly employed to complement experimental high pressure research. Here, a brief overview of the underlying theory and available codes is provided, followed by some applications. The influence of the choice of the exchange-correlation functional on predicted structural parameters and physical properties is discussed. lem is not guaranteed. Secondly, the computational effort required is, for most problems, moderate, so that a few days of cpu time on a moderately sized cluster are sufficient to solve a problem. Of course, there are numerous questions, such as large scale molecular dynamics simulations to understand melting which require extre-
Chemistry-A European …, 2004
MoP has been shown experimentally to be an active catalyst in the hydrodenitrogenation of o-propy... more MoP has been shown experimentally to be an active catalyst in the hydrodenitrogenation of o-propylaniline. We investigate the structure and the energetics of the o-propylaniline adsorption on the Mo-terminated MoP(001) surface. Detailed information on the structure of the free MoP(001) surface and on the structure and adsorption energy of o-propylaniline on MoP(001) is obtained by using density functional theory. The transition state, reaction path, and the energy barrier are reported for one of the branches of the HDN reaction network that leads to the formation of propylbenzene by hydrogenolysis of the C-N bond.
Parallel Computing, 2000
In this and a preceding paper, we provide an introduction to the Fujitsu VPP range of vector±para... more In this and a preceding paper, we provide an introduction to the Fujitsu VPP range of vector±parallel supercomputers and to some of the computational chemistry software available for the VPP. Here, we consider the implementation and performance of seven popular chemistry application packages. The codes discussed range from classical molecular dynamics to semiempirical and ab initio quantum chemistry. All have evolved from sequential codes, and have typically been parallelised using a replicated data approach. As such they are well suited to the large-memory/fast-processor architecture of the VPP. For one code, CASTEP, a distributed-memory data-driven parallelisation scheme is presented. Ó
Parallel Computing, 2000
In this and the following paper, we provide an introduction to the Fujitsu VPP range of vector±pa... more In this and the following paper, we provide an introduction to the Fujitsu VPP range of vector±parallel supercomputers and to some of the computational chemistry software available for the VPP. Here, we consider the hardware and the design of software to exploit its capabilities. The VPP employs proprietary vector processors connected via a crossbar switch in a distributed-memory architecture. High single-node performance requires consideration of vector operand lengths, arithmetic pipe utilisation and memory-to-CPU bandwidth. Most parallel chemistry applications use either explicit`message-passing' or a Ôglobal-memoryÕ paradigm, and benchmark results are presented for the communications performance of MPI, Linda and the Global Arrays. Ó
Ukrainian Journal of Physics
ABSTRACT
American Mineralogist, 2000
... Chaplin, T., Price, GD, and Ross, NL (1998) Computer simulation of the infrared and Raman act... more ... Chaplin, T., Price, GD, and Ross, NL (1998) Computer simulation of the infrared and Raman activity of pyrope garnet, and assignment of calculated modes to specific atomic motions. American Mineralogist, 83, 841847.[Abstract][Web of Science][GeoRef]. ...
![Research paper thumbnail of Pressure-induced spin collapse of octahedrally coordinated Mn 3 + in the tetragonal hydrogarnet henritermierite Ca 3 Mn 2 [ SiO 4 ] 2 [ O 4 H 4 ]](https://attachments.academia-assets.com/42158845/thumbnails/1.jpg)
](Physical Review B, 2015
The high-pressure behavior of andradite garnet, Ca 3 Fe 2 [SiO 4 ] 3 , was studied at pressures u... more The high-pressure behavior of andradite garnet, Ca 3 Fe 2 [SiO 4 ] 3 , was studied at pressures up to 80 GPa using single-crystal synchrotron x-ray diffraction, Raman spectroscopy, and quantum mechanical calculations based on density functional theory. An isosymmetric phase transition was observed in the pressure range between 60 and 70 GPa, which is associated with a gradual high-spin to low-spin electronic transition in Fe 3+ . Experimental structural data before and after the phase transition are in excellent agreement with the theoretically predicted structural compression of the high-spin and low-spin phases, respectively. While the overall unit-cell volume is reduced by about 2.5% across the phase transition, a collapse of about 10% of the FeO 6 octahedral volume is observed, attributed to the reduced Fe-O bond lengths associated with low-spin Fe 3+ . In combination with earlier data the present study shows that a spin collapse of Fe 3+ in FeO 6 octahedra will be triggered if the Fe-O bond length reaches a critical value of d(Fe-O) < ≈ 1.9Å. Earlier reported results for the compressibility of the cation coordination polyhedra are substantially revised, with B FeO 6 = 195(2) GPa, B CaO 8 = 104(2) GPa, and B SiO 4 = 348(11) GPa for the high-spin phase. The mode Grüneisen parameters range between 0.61 and 1.34. The computed spin-pairing energy is ≈4.2 eV at 0 GPa.
American Mineralogist, 2000
Properties of Complex Inorganic Solids 2, 2000
MRS Proceedings, 1993
We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using ab ... more We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using ab initio total energy calculations. The calculated diffusion barriers are in excellent agreement with experimental estimates. Using a large supercell we resolve the controversy regarding the binding geometry and migration path for the adatom, and investigate the influence of the adatom on the buckling of Si dimers. The adatom induces a buckling defect that is frequently observed using scanning tunneling microscopy (STM); therefore the study of single adatoms may be experimentally accessible.
Properties of Complex Inorganic Solids, 1997
Physical review letters, Jan 5, 1993
Physical review. B, Condensed matter, Jan 15, 1994
Physical review. B, Condensed matter, Jan 15, 1993
The interactions of the "magic" Al&2Si clusters are studied by first-principles electron-structur... more The interactions of the "magic" Al&2Si clusters are studied by first-principles electron-structure calculations. It is shown that clusters arranged into the fcc lattice do not conserve their separatedcluster icosahedral structure but coalesce to form a close-packed metal.
Physical review. B, Condensed matter, Jan 15, 1995
... VOLUME 51, NUMBER 23 Electronic and elastic properties of edge dislocations in Si Feng Liu, M... more ... VOLUME 51, NUMBER 23 Electronic and elastic properties of edge dislocations in Si Feng Liu, Mark Mostoller, V. Milman,* MF Chisholm, and Theodore ... Calcula-tions were done for dipole separations of 7.5-22.9 A along the direction of the Burgers vector in the relaxed samples ...
Physical review. B, Condensed matter, Jan 15, 1995
We use ab initio pseudopotential electronic-structure methods to de d scribe successfull both the... more We use ab initio pseudopotential electronic-structure methods to de d scribe successfull both the dey tailed static structures and the structural transformation in B&03 y . p 0 cr stals. Em loying a reduced cell model the structural transformavo ume, wi u 1 th f 11 relaxation of all internal coordinates, our calculations~~~~r ahedral tion from the polymorph containing e 3 r' h ' '
Physical review. B, Condensed matter, Jan 15, 1994
ABSTRACT We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface ... more ABSTRACT We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using [ital ab] [ital initio] total-energy calculations. The theoretical diffusion barriers are in excellent agreement with experimental estimates. Using a large supercell we resolve the controversy regarding the binding geometry and migration path for the adatom, and investigate its influence on the buckling of Si dimers. We find that the adatom induces a buckling defect that is frequently observed using scanning tunneling microscopy, indicating that the study of a single adatom may be experimentally accessible.
Physical review letters, Jan 5, 1993
Progress in Materials Science, 1994
Zeitschrift für Kristallographie – Crystalline Materials, 2014
Density functional theory based calculations are commonly employed to complement experimental hig... more Density functional theory based calculations are commonly employed to complement experimental high pressure research. Here, a brief overview of the underlying theory and available codes is provided, followed by some applications. The influence of the choice of the exchange-correlation functional on predicted structural parameters and physical properties is discussed. lem is not guaranteed. Secondly, the computational effort required is, for most problems, moderate, so that a few days of cpu time on a moderately sized cluster are sufficient to solve a problem. Of course, there are numerous questions, such as large scale molecular dynamics simulations to understand melting which require extre-
Chemistry-A European …, 2004
MoP has been shown experimentally to be an active catalyst in the hydrodenitrogenation of o-propy... more MoP has been shown experimentally to be an active catalyst in the hydrodenitrogenation of o-propylaniline. We investigate the structure and the energetics of the o-propylaniline adsorption on the Mo-terminated MoP(001) surface. Detailed information on the structure of the free MoP(001) surface and on the structure and adsorption energy of o-propylaniline on MoP(001) is obtained by using density functional theory. The transition state, reaction path, and the energy barrier are reported for one of the branches of the HDN reaction network that leads to the formation of propylbenzene by hydrogenolysis of the C-N bond.
Parallel Computing, 2000
In this and a preceding paper, we provide an introduction to the Fujitsu VPP range of vector±para... more In this and a preceding paper, we provide an introduction to the Fujitsu VPP range of vector±parallel supercomputers and to some of the computational chemistry software available for the VPP. Here, we consider the implementation and performance of seven popular chemistry application packages. The codes discussed range from classical molecular dynamics to semiempirical and ab initio quantum chemistry. All have evolved from sequential codes, and have typically been parallelised using a replicated data approach. As such they are well suited to the large-memory/fast-processor architecture of the VPP. For one code, CASTEP, a distributed-memory data-driven parallelisation scheme is presented. Ó
Parallel Computing, 2000
In this and the following paper, we provide an introduction to the Fujitsu VPP range of vector±pa... more In this and the following paper, we provide an introduction to the Fujitsu VPP range of vector±parallel supercomputers and to some of the computational chemistry software available for the VPP. Here, we consider the hardware and the design of software to exploit its capabilities. The VPP employs proprietary vector processors connected via a crossbar switch in a distributed-memory architecture. High single-node performance requires consideration of vector operand lengths, arithmetic pipe utilisation and memory-to-CPU bandwidth. Most parallel chemistry applications use either explicit`message-passing' or a Ôglobal-memoryÕ paradigm, and benchmark results are presented for the communications performance of MPI, Linda and the Global Arrays. Ó
Ukrainian Journal of Physics
ABSTRACT
American Mineralogist, 2000
... Chaplin, T., Price, GD, and Ross, NL (1998) Computer simulation of the infrared and Raman act... more ... Chaplin, T., Price, GD, and Ross, NL (1998) Computer simulation of the infrared and Raman activity of pyrope garnet, and assignment of calculated modes to specific atomic motions. American Mineralogist, 83, 841847.[Abstract][Web of Science][GeoRef]. ...
Physical Review B, 2015
The high-pressure behavior of andradite garnet, Ca 3 Fe 2 [SiO 4 ] 3 , was studied at pressures u... more The high-pressure behavior of andradite garnet, Ca 3 Fe 2 [SiO 4 ] 3 , was studied at pressures up to 80 GPa using single-crystal synchrotron x-ray diffraction, Raman spectroscopy, and quantum mechanical calculations based on density functional theory. An isosymmetric phase transition was observed in the pressure range between 60 and 70 GPa, which is associated with a gradual high-spin to low-spin electronic transition in Fe 3+ . Experimental structural data before and after the phase transition are in excellent agreement with the theoretically predicted structural compression of the high-spin and low-spin phases, respectively. While the overall unit-cell volume is reduced by about 2.5% across the phase transition, a collapse of about 10% of the FeO 6 octahedral volume is observed, attributed to the reduced Fe-O bond lengths associated with low-spin Fe 3+ . In combination with earlier data the present study shows that a spin collapse of Fe 3+ in FeO 6 octahedra will be triggered if the Fe-O bond length reaches a critical value of d(Fe-O) < ≈ 1.9Å. Earlier reported results for the compressibility of the cation coordination polyhedra are substantially revised, with B FeO 6 = 195(2) GPa, B CaO 8 = 104(2) GPa, and B SiO 4 = 348(11) GPa for the high-spin phase. The mode Grüneisen parameters range between 0.61 and 1.34. The computed spin-pairing energy is ≈4.2 eV at 0 GPa.
American Mineralogist, 2000
Properties of Complex Inorganic Solids 2, 2000
MRS Proceedings, 1993
We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using ab ... more We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using ab initio total energy calculations. The calculated diffusion barriers are in excellent agreement with experimental estimates. Using a large supercell we resolve the controversy regarding the binding geometry and migration path for the adatom, and investigate the influence of the adatom on the buckling of Si dimers. The adatom induces a buckling defect that is frequently observed using scanning tunneling microscopy (STM); therefore the study of single adatoms may be experimentally accessible.
Properties of Complex Inorganic Solids, 1997
Physical review letters, Jan 5, 1993
Physical review. B, Condensed matter, Jan 15, 1994
Physical review. B, Condensed matter, Jan 15, 1993
The interactions of the "magic" Al&2Si clusters are studied by first-principles electron-structur... more The interactions of the "magic" Al&2Si clusters are studied by first-principles electron-structure calculations. It is shown that clusters arranged into the fcc lattice do not conserve their separatedcluster icosahedral structure but coalesce to form a close-packed metal.
Physical review. B, Condensed matter, Jan 15, 1995
... VOLUME 51, NUMBER 23 Electronic and elastic properties of edge dislocations in Si Feng Liu, M... more ... VOLUME 51, NUMBER 23 Electronic and elastic properties of edge dislocations in Si Feng Liu, Mark Mostoller, V. Milman,* MF Chisholm, and Theodore ... Calcula-tions were done for dipole separations of 7.5-22.9 A along the direction of the Burgers vector in the relaxed samples ...
Physical review. B, Condensed matter, Jan 15, 1995
We use ab initio pseudopotential electronic-structure methods to de d scribe successfull both the... more We use ab initio pseudopotential electronic-structure methods to de d scribe successfull both the dey tailed static structures and the structural transformation in B&03 y . p 0 cr stals. Em loying a reduced cell model the structural transformavo ume, wi u 1 th f 11 relaxation of all internal coordinates, our calculations~~~~r ahedral tion from the polymorph containing e 3 r' h ' '
Physical review. B, Condensed matter, Jan 15, 1994
ABSTRACT We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface ... more ABSTRACT We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using [ital ab] [ital initio] total-energy calculations. The theoretical diffusion barriers are in excellent agreement with experimental estimates. Using a large supercell we resolve the controversy regarding the binding geometry and migration path for the adatom, and investigate its influence on the buckling of Si dimers. We find that the adatom induces a buckling defect that is frequently observed using scanning tunneling microscopy, indicating that the study of a single adatom may be experimentally accessible.