Programs in Physics & Physical Chemistry
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Programs in Physics & Physical Chemistry |
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| [Licence| Download | E-mail| New Version Template] aeec_v1_0.tar.gz(72 Kbytes) | ||
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| Manuscript Title: Optimized Multiple Quantum MAS Lineshape Simulations in Solid State NMR | ||
| Authors: William J. Brouwer, Michael C. Davis, Karl T. Mueller | ||
| Program title: mqmasOPT | ||
| Catalogue identifier: AEEC_v1_0 Distribution format: tar.gz | ||
| Journal reference: Comput. Phys. Commun. 180(2009)1973 | ||
| Programming language: C, OCTAVE. | ||
| Computer: UNIX/Linux. | ||
| Operating system: UNIX/Linux. | ||
| Has the code been vectorised or parallelized?: Yes | ||
| RAM: Example: (1597 powder angles)×(200 Samples)×(81 F2 frequency pts)×(31 F1 frequency points)= 3.5M, SMP AMD opteron | ||
| Keywords: Nuclear Magnetic Resonance, Multiple Quantum Magic Angle Spinning, OpenMP, Sobol sequence, quasi-random numbers, simulated annealing, distribution functions, quadrupole interaction. | ||
| PACS: 02.70.-c, 07.05.Tp, 32.30.Dx. | ||
| Classification: 2.3. | ||
External routines: OCTAVE (http://www.gnu.org/software/octave/), GNU Scientific Library ( http://www.gnu.org/software/gsl/), OPENMP (http://openmp.org/wp/) | ||
Nature of problem: The optimal simulation and modeling of multiple quantum magic angle spinning NMR spectra, for general systems, especially those with mild to significant disorder. The approach outlined and implemented in C and OCTAVE also produces model parameter error estimates. | ||
Solution method: A model for each distinct chemical site is first proposed, for the individual contribution of crystallite orientations to the spectrum. This model is averaged over all powder angles[1], as well as the (stochastic) parameters; isotropic chemical shift and quadrupole coupling constant. The latter is accomplished via sampling from a bi-variate Gaussian distribution, using the Box-Muller algorithm to transform Sobol (quasi) random numbers[2]. A simulated annealing optimization is performed, and finally the non-linear jackknife[3] is applied in developing model parameter error estimates. | ||
Additional comments: The distribution contains a script, mqmasOpt.m, which runs in the OCTAVE language workspace. | ||
Running time: Example: (1597 powder angles)×(200 Samples)×(81 F2 frequency pts)×(31 F1 fre- quency points)=58.35 seconds, SMP AMD opteron | ||
References: | ||
| [1] | S. K. Zaremba, Annali di Matematica Pura ed Applicata 73, 293 (1966) | |
| [2] | H. Niederreiter, Random number generation and quasi-Monte Carlo methods, SIAM, 1992 | |
| [3] | T. Fox, D. Hinkley, K. Larntz, Technometrics 22, 29 (1980) | |
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