Dreifðir tölvureikningar og langtíma framvinda í efnum - verkefnislok
Niðurstöður verkefnisins "Dreifðir tölvureikningar og langtíma framvinda í efnum" - "Distributed computing and long time scale evolution in materials" voru betrumbætur á EON-kóðanum, sérstaklega varðandi getu og notagildi. Gríðarlega mikilvægur var möguleikinn á því að nota EON á bestunarvandamál og að nota fjölbreyttara úrval módela fyrir samspil atóma og einnig fyrir jarðhita. Með því að breyta EON í forrit með meira notagildi hefur það orðið meira aðlaðandi fyrir stærri rannsóknarhópa.
Heiti verkefnis: Dreifðir tölvureikningar og langtíma framvinda í efnum
Verkefnisstjóri: Andreas Pedersen, Raunvísindastofnun Háskólans
Tegund styrks: Verkefnisstyrkur
Styrkár: 2010-2012
Fjárhæð styrks: 12,54 millj. kr.
Tilvísunarnúmer Rannís: 100010
Dínamísk hegðun yfirborðs íss hefur verið rannsakað með EON og með útreikningum á uppbyggingu gull-nanóklasa hefur verið ákvarðað að slíkir klasar séu öðruvísi en áætlað var og að ný ætt með lokaðri uppbyggingu er tilnefnd. Að lokum var uppbygging á formlausum kísli rannsökuð með þeirri niðurstöðu að tóm sem einkennast af fjórum atómum sem hafa einungis þrjú nágrannaatóm - eins og í kristölluðum kísli - eru ekki til í formlausum fasa. Þar sem allar niðurstöður framkvæmdra útreikninga eru með fordæmalausri nákvæmni eða tímaskala, hefur verið mögulegt að rannsaka ný fyrirbæri, sem eru óaðgengileg með öðrum hugbúnaði. Má því búast við að niðurstöðurnar hafi varanleg áhrif á viðkomandi rannsóknarsviði.
News release
The outcome of the project 'Distributed computing and long time scale evolution in materials' was an enhancement of the EON code in terms of capability and applicability. Of special importance is the possibility to apply EON to global optimization problems and to utilize a wider range of models for the atomic interactions and geothermal models. By transforming EON into a program with a wider applicability it has become attractive to a larger group of researchers.
By applying the EON code the dynamical behavior of water ice surfaces has been investigated, and from simulations of the structure of gold nanoclusters it has been determined that such clusters are different from what usually assumed and a new family of closed shelled structures proposed. Finally, the structure of amorphous silicon has also been investigated and it is concluded that vacancies characterized by four undercoordinated atoms -as observed in crystalline silicon- do not exist in the amorphous phase. As all results from the conducted simulations are of an unprecedented accuracy or time scale it has been possible to study novel phenomena, which are inaccessible with other simulation tools and the findings are expected to make a lasting impact in their respective research fields.
Papers
1. Efficient Sampling of Saddle Points with the Minimum-Mode Following Method
A. Pedersen, S. Hafstein and H. Jónsson
SIAM Journal on Scientific Computing, 32, 633 (2011).
2. The charging profile of dust grains in the environment of Young Stellar Objects
A. Pedersen and A. I. Gomez de Castro
The Astrophysical Journal, 740, 77 (2011)
3. Simulated Annealing with Coarse Graining and Distributed Computing,
A. Pedersen, J-C. Berthet and H. Jónsson
Lecture Notes in Computer Science 7134, 34 (2012).
4. Global Optimization of Reservoir Models by Mapping Out Object Function Minima and Saddle Points
M. Plasencia, A. Pedersen, A. Arnaldsson and H. Jónsson
Proc. 37th Workshop on Geothermal Reservoir Engineering at Stanford University
Jan. 30 - Feb. 1 (2012)
5. Geothermal Model Calibration using a Global Minimization Algortihm based on Finding Saddle Points as well as Minima of the Objective Function
M. Plasencia, A. Pedersen, A. Arnaldsson and H. Jónsson
Proc. TOUGH Symposium 2012 at Lawrence Berkeley National Laboratory
Sep. 17 - Sep. 19 (2012)
6. Long-timescale Simulations of Diffusion in Molecular Solids
L. Karssemeijer, A. Pedersen, H. Jónsson and H. Cuppen
Physical Chemistry Chemical Physics, 10844, 14 (2012)
7. Tunability of the terahertz space-charge modulation in a vacuum microdiode
P. Jonsson, M. Ilkov, A. Manolescu, A. Pedersen, and A. Valfells
Physics of Plasmas 20, 023107 (2013)
8. Stability and mobility of vacancy–H complexes in Al
M. Benediktsson, K. Mýrdal, P. Maurya and A Pedersen
Journal of Physics: Condensed Matter; 25, 375401 (2013)
9. Geothermal Model Calibration using a Global Minimization Algorithm based on finding Saddle Points and Minima of the Objective Function
M. Plasencia, A. Pedersen, A. Arnaldsson J. C. Berthet and H. Jónsson
Computers & Geosciences (2013)
To be published
10. Simulated amorphous silicon consistent with experimental measurements
A. Pedersen, L. Pizzagalli and H. Jónsson
11. Structural and electronic characterization of amorphous silicon network upon vacancy creation
A. Pedersen, L. Pizzagalli and H. Jónsson
12. Long time scale simulations of ice surfaces with and without an H2O admolecule
A. Pedersen, L. Karssemeijer, H. Cuppen and H. Jónsson
13. Eon: Software for long time scale simulations of atomic scale systems
S. T. Chill, M. Welborn, R. Terrell, L. Zhang, J.-C. Berthet, A. Pedersen, H. Jónsson and G. Henkelman
14. A simulation study of the structure of magic size Au nanoclusters
A. Pedersen and H. Jónsson
