quantum systems

 a new material found in our group (with Carlos L. Reis & José Luís Martins, 2007)

I initiated my research studying quantum many-body systems at finite temperature. This is a research topic where high performance computing together with the development of new algorithms proceed hand in hand and provide an instrumental help in the advancement of science. I started by studying atomic nuclei (science at the femto-scale), and part of my PhD thesis has been devoted to such systems, although I ended up my thesis work studying atomic clusters which, although seemingly unrelated, share many of the features known for decades in atomic nuclei, but at a scale 6 orders of magnitude larger (science at the nano-scale). On the other hand, there is little doubt on the nature of the interactions between atoms, in contrast with the situation involving atomic nuclei. My research in atomic clusters has expanded into the interface area between physics, chemistry & molecular biology or biochemistry, for system sizes at which quantum effects play a role, including the ubiquitous nanotech hype. This happens up to surprisingly large scales, canonically known as mesoscopic domains, where most people ignores them (it is only a matter of time). Along this research process, I had the privilege of working with some great scientists and to participate in exciting projects involving large scale computer simulations. A subgroup belongs to the list of co-authors of the publications listed below in reverse chronological order. 


A. nano-scale systems & nano-scale designed materials

133. Vibrational spectra of silicon cage clusters doped with Ti, Zr, or Hf
Carlos L. Reis, Jorge M Pacheco
Physical Review B82 (2010) 155440

[pdf] , [e-link]

115. Hierarchically constrained dynamics and emergence of complex behaviour in nano-hybrids
Luís D. Carlos, J. M. Pacheco, Rute A. S. Ferreira, António L. L. Videira
SMALL  (2009) (accepted)
[pdf] , [e-link]

114. Bulk materials made of silicon cage clusters doped with Ti, Zr, or Hf
Carlos L. Reis, J. M. Pacheco
J. Physics Condensed Matter (2009) (accepted)
[pdf] , [e-link]

090. Stability analysis of a bulk material built from silicon cage clusters: A first principles approach
Carlos L. Reis, José Luís Martins, J. M. Pacheco
Physics Review B 76 (2007) 233406
[pdf] , [e-link]

074. Silicon-metal clusters: nano-templates for cluster assembled materials
G. K. Gueorguiev, J. M. Pacheco, S. Stafström,
Thin Solid Films 515 (2006) 1192-1196
[pdf] , [e-link]

052. Quantum size effects in the polarizability of carbon fullerenes
G. K. Gueorguiev, J. M. Pacheco, David Tomanek,
Virtual Journal of Nanoscale Science and Technology, 9-4 (2004)

051. Quantum size effects in the polarizability of carbon fullerenes
G. K. Gueorguiev, J. M. Pacheco, David Tomanek,
Phys. Rev. Lett. 92 (2004) 215501

050. Shapes of cagelike metal carbide clusters: First-principles calculations
G. K. Gueorguiev, J. M. Pacheco,
Phys. Rev. B68 (Rapid Communications) (2003) 241401

049. First-principles norm-conserving pseudopotential with explicit incorporation of semicore states
Carlos L. Reis, J. M. Pacheco, José Luís Martins,
Phys. Rev. B68 (2003) 155111

048. Silicon and metal nanotemplates: Size and species dependence of structural and electronic properties
G. K. Gueorguiev, J. M. Pacheco,
J. Chem. Phys. 119 (2003) 10313-10317

047. First-principles study of the possibility of condensed phases of endohedral silicon cage clusters
J. M. Pacheco, G. K. Gueorguiev, José Luís Martins
Phys. Rev. B66 (2002) 033401

046. Structural Identification of MetCars
G. K. Gueorguiev, J. M. Pacheco
Virtual Journal of Nanoscale Science and Technology, 5-11 (2002)

045. Structural Identification of MetCars
G. K. Gueorguiev, J. M. Pacheco
Phys. Rev. Lett. 88 (2002) 115504

044. Structural and electronic properties of C 36
G. K. Gueorguiev, J. M. Pacheco
J. Chem. Phys. 114 (2001) 6068

043. Influence of Exchange-Correlation potential in Density Functional calculations on polarizabilities and absorption spectra of alkali-metal clusters
S. A. J. van Gisbergen, J. M. Pacheco, E. J. Baerends
Phys. Rev. A63 (2001) 063201

042. Prediction of Liquid C 60 from ab-initio intermolecular potential, in Modelling Complex Systems
A. L. Ferreira, J. M. Pacheco, J. P. Prates-Ramalho
Sixth Granada Lectures on Computational Physics,
AIP Conference Proceedings 574 (2001) 218
(L. Garrido, J. Marro, Edts.)

041. Monte Carlo simulations with first-principles energies
J. M. Pacheco, José Luís Martins
Density Functional Theory and its Applications to Materials,
AIP Conference Proceedings 571 (2001) 166
(V. E. van Doren, K. van Alsenoy, P. Geerlings, Edts.) ´

040. Highly efficient implementation of a Gaussian program to computing total energy of giant molecules
J. M. Pacheco, José Luís Martins
Lecture Notes in Computer Science 1981 (2001) 230

039. Phase diagram of C 60 from ab-initio intermolecular potential
A. L. Ferreira, J. M. Pacheco, J. P. Prates-Ramalho
J. Chem. Phys. 113 (2000) 738

038. Application of the Jellium Model and its Refinements to the Study of the Electronic Properties of Metal Clusters
Walter Ekardt, W.-D. Schöne.,J. M. Pacheco
"Metal Clusters"
W. Ekardt (Edt.)
John Wiley & Sons (1999)

037. Reply... "Shape Phase-Transitions in the Absorption Spectra ofAtomic Clusters"
J. M. Pacheco, W. D. Schöne
Phys. Rev. Lett. 81 (1998) 5703

036. Towards a First-Principles Determination of the Phase Diagram of C 60
J. M. Pacheco J. P. Prates Ramalho
Condensed Matter Theories, vol. 13
J. da Providência et al. (Edts.)
Nova Science Publishers (1998)

035. Ionic and Temperature Aspects of the Photoresponse of Metallic Clusters
J. M. Pacheco
Czechoslovak Journal of Physics 48 (1998) 749

034. Effects Of Geometry In the Elastic Scattering of Electrons by C 60 Molecules
A. N. Ipatov, W. P. Ekardt, J. M. Pacheco
J. Phys. B31 (1998) L511-L517

033. Shape Phase-Transitions in the Absorption Spectra ofAtomic Clusters
J. M. Pacheco , W. D. Schöne
Phys. Rev. Lett. 79 (1997) 4986

032. First-Principles Determination of the Dispersion Interaction between
Fullerenes and their Inter-Molecular Potential
J. M. Pacheco , J. P. Prates Ramalho
Phys. Rev. Lett. 79 (1997) 3873

031. Plasmons and Excitons in Many-electron systems and the Optical response of Atomic Clusters
J. M. Pacheco , W. P. Ekardt
Z. Phys. B103 (1997) 327

030. Ab-Initio Pseudopotential Calculation of the Photo-Response of Metal Clusters
J. M. Pacheco, José Luís Martins
J. Chem. Phys. 106 (1997) 6039

029. Role of self-interaction effects in the geometry optimization of small metal clusters
J. M. Pacheco , W. Ekardt, W. D. Schöne
Europhys. Lett. 34 (1996) 13

028. Microscopic structure of the surface plasmon in fullerenes
J. M. Pacheco
Surf. Rev. and Lett. 3 (1996) 753

027. Reintroducing the ionic structure in the jellium model for metal clusters:
pseudopotential perturbation theory
J. M. Pacheco, W. Ekardt, W. D. Schöne
Surf. Rev. and Lett. 3 (1996) 313

026. Monolayer metal coverage of fullerenes: The optical response
J. M. Pacheco, F. Alasia, H. E. Roman, R. A. Broglia
Z. Phys. D37 (1996) 277

025. Anisotropic effects in the optical spectra of magic metal clusters: the role of ionic structure
W. D. Schöne, W. Ekardt, J. M. Pacheco
Z. Phys. D36 (1996) 65

024. Effective particle-hole interaction and the optical response of simple metal clusters
W. Ekardt, J. M. Pacheco
Phys. Rev. B52 (1995) 16864

023. Response of metal clusters to elastic electron impact
M. Bernath, O. Dragún, M. R. Spinella, H. Massmann, J. M. Pacheco
Phys. Rev. A52 (1995) 2173

022. Microscopic structure of collective charge density oscillations in C 60 and C 70
M. S. Hansen, J. M. Pacheco, G. Onida
Z. Phys. D35 (1995) 149

021. Size dependent plasmons in metal clusters
W. Ekardt, J. M. Pacheco and Z. Penzar
Comments in Atomic and Molecular Physics 31 (1995) 291

020. The optical response of anionic alkali metal clusters
J. M. Pacheco , W. Ekardt
"Atomic and Nuclear Clusters" (Springer-Verlag, Berlin, 1995), pag.79

019. The reintroduction of the ionic skeleton in the jellium model for metal clusters:
pseudopotential perturbation theory
W. D. Schöne, W. Ekardt, J. M. Pacheco
Phys. Rev. B50 (1994) 11079

018. Single-particle and collective degrees of freedom in C 60
F. Alasia, R. A. Broglia, Ll. Serra, G. Coló, J. M. Pacheco
J. Phys. B: Mol. Opt. Phys. 27 (1994) L643

017. Microscopic description of the plasmon resonance in small deformed metal clusters
M. Bernath, M. E. Spina, J. M. Pacheco
Phys. Rev. B49 (1994) 10764

016. The van de Waals Interaction between alkali microclusters
J. M. Pacheco , W. Ekardt
Mod. Phys. Lett. B7 (1993) 573

015. The photoabsorption cross section of negatively charged alkali metal clusters
J. M. Pacheco , W. Ekardt
Phys. Rev. B47 (1993) 6667

014. Response of finite many-electron systems beyond the time dependent
local density approximation: Application to small metal clusters
J. M. Pacheco , W. Ekardt
Annalen der Physik ( Leipzig) 1 (1992) 254

013. Microscopic calculation of the van der Waals interaction between small metal clusters
J. M. Pacheco , W. Ekardt
Phys. Rev. Lett. 68 (1992) 3694

012. Effects of motional narrowing on the plasmon resonance in small metal clusters
W. E. Ormand, J. M. Pacheco, S. Sanguinetti, G. Benedek, R. A. Broglia
Z. Phys. D24 (1992) 401

011. A new formulation of the dynamical response of many-electron systems and the
photoabsorption cross section of small metal clusters
J.M. Pacheco and W. Ekardt
Z. Phys. D24 (1992) 65

010. Role of self-interaction corrections in the photoabsorption cross section of small metal cluster
J. M. Pacheco and W. Ekardt,
Proceedings of the NATO conference Physics and Chemistry of finite systems:
From clusters to crystals, ed. by P. Jena, S. N. Khanna and B. K. Rao,
NATO ASI series C, vol. 374 (Kluwer Academic Publishers, 1992)

009. Optical response of metal microclusters: Atomic analog of the giant dipole resonance in nuclei
R. A. Broglia, J. M. Pacheco, C. Yannouleas
Phys. Rev. B44 (1991) 5901

008. The intrinsic line width of the plasmon resonances in metal microclusters at very low temperatures: Quantal surface fluctuations
J. M. Pacheco , R. A. Broglia, B. R. Mottelson
Z. Phys. D21 (1991) 289

007. Microscopic structure of the plasma resonance in charged potassium microclusters
C. Yannouleas, J. M. Pacheco and R. A. Broglia
Phys. Rev. B41 (1990) 6088

006. Effect of surface fluctuations in the line shape of plasma resonances in small metal clusters
J. M. Pacheco and R. A. Broglia
Phys. Rev. Lett. 62 (1989) 1400


B. femto-scale systems

005. Algebraic manipulation of the states associated with the U(5) x O(5) x O(3) chain of groups: Orthonormalization and matrix elements
C. Yannouleas, J. M. Pacheco
Computer Physics Communications 54 (1989) 315

004. Time dependent Hartree-Fock calculation of the escaping width of the giant monopole resonance in Oxygen 16
J. M. Pacheco , E. Maglione and R. A. Broglia
Phys. Rev. C37 (1988) 2257

003. Fluctuations in the Shape Transitions of Hot Nuclei
J. M. Pacheco , C. Yannouleas and R. A. Broglia
Phys. Rev. Lett. 61 (1988) 294

002. An algebraic program for the states associated with the U(5) x O(5) x O(3) chain of groups
C. Yannouleas, J. M. Pacheco
Computer Physics Communications 52 (1988) 85

001. Damping of nuclear excitations at finite temperature
P. F. Bortignon, R. A. Broglia, G. F. Bertsch, J. M. Pacheco
Nucl. Phys. A460 (1986) 149