2015 Fiscal Year Research-status Report
| Project/Area Number |
26410013
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| Research Institution | Nagoya University |
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Principal Investigator |
Irle Stephan 名古屋大学, 理学部(WPI), 教授 (00432336)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | nanotubes / DFTB/MD / rare events / KMC |
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| Outline of Annual Research Achievements |
We had proposed a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. In this year we have succeeded in the implementation of this algorithm, which we call "fly-KMC". Starting from any given equilibrium structure, this global reaction route mapping (GRRM)-KMC algorithm performs a one-step GRRM search to identify all surrounding transition state barriers. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculated on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde, and surface carbon diffusion on an iron nanoparticle, relevant for the study of carbon nanotube growth in the final year of the project. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding (DFTB) potential. We are hopeful to extend the applicability of fly-KMC to nanotube growth on metal alloy nanoparticles, which has never before been attempted, using the DFTB parameters developed in the first year of the project.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We are within our plan for the 3-year project by having implemented the fly-KMC program, which combines KMC, DFTB, and GRRM methodologies to simulate rare events on long timescales. The development of this program is the centerpiece of this project, and its successful completion can only be called a success. A paper describing the program has been submitted on April 25 to a peer-reviewed, international journal.
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| Strategy for Future Research Activity |
There remain still issues related to the efficiency of the fly-KMC code, which have to be addressed in the final year of the project (FY2016). In addition, the fly-KMC code now needs to be applied to the proposed study of carbon nanotube growth on metal alloy nanoparticles, which will also happen during FY2016.
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| Causes of Carryover |
A collaborative trip to Stony Brook University and Oak Ridge National Lab was postponed for technical reasons to April, 2016.
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| Expenditure Plan for Carryover Budget |
The remaining amount was spent on a collaborative trip to Stony Brook University and Oak Ridge National Lab was postponed for technical reasons in April 3-20, 2016.
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