Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Darya Aleinikava Applicant's institution: ANL Applicant's division: CSE Project Name: Anharmonic_systems Project title: Analysis of dynamical complexities of highly anharmonic systems Associated funding: Other Systems: High-performance GPU cluster Golem Science: The goal of this project is to study the dynamical complexities of systems with arbitrary degree of anharmonicity. The first objective of this work is to calculate a statistical descriptor, such as density of states (DOS), and use it to analyze the properties of various structures, such as molecules and clusters, as a function of their composition, size, equilibrium configuration, etc. DOS is the central figure of statistical mechanics since it is the basis for computation of all thermodynamic quantities, and it also plays a major role in a theory of chemical kinetics because it allows a direct evaluation of reaction rates. The non-trivial problem of finding DOS for arbitrary anharmonic systems has been researched extensively over the last 60 years, but no exact solution that would be applicable in all cases was found. We developed an original quantum algorithm with provides an exact solution for arbitrary (including highly anharmonic) systems. This project will involve MD simulations, which are performed on various nanoscale systems with the use of many-body potentials. Such simulations will produce power spectra, which serve as an input into a newly developed algorithm, yielding the exact anharmonic density of states thus eliminating the need to use various approximations. As the second aspect of the project we will address the problem of mixing, where we plan to utilize such descriptors as mixing energy and mixing coefficient, collected during MD simulation runs, to investigate the structural changes of different isomers during high-energy dynamics which is of particular importance in the study of multiple-steps melting transitions. Project description: Efficient codes for original algorithm and MD simulations were developed and extensively tested on a high-performance GPU cluster Golem. We have successfully applied our methodology to Ar, Ne, Al, Ni, and mixed clusters of sizes N=3, 7, 13 and 55. We are planning to use our approach for systems of different compositions with larger sizes, up to N=147 and higher. The number of runs (at different energies) for each system to get a reasonable density of states energy dependence is approximately 15, thus MD simulations time for 70 structures will be 30 core-hours*15 runs*70 structures=31500 core-hours. The new algorithm is implemented in parallel, and its average run will require 8 cores/node * 2 nodes * 25 hours of run time = 400 core-hours, thus the computation of a complete DOS curve for a given system will amount to 400 core-hours *15 runs=6000 core-hours. Including MD simulations time, the total computational time for 70 structures (different in size and composition) will be 31500 core-hours+ 6000 core-hours*70 structures+1000 hours development=452,500 core-hours. The second aspect of the project will be incorporated in MD runs mentioned above. Out of requested 452,500 core-hours, 7% of the time will be allocated for single-core jobs. The number of people to run these simulations is 1. Project URL: Requested allocation: 452500 Q1: 113125 Q2: 113125 Q3: 113125 Q4: 113125 Justification: The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System