AUTOSURF is a powerful software designed to robustly compute electronic energies and incorporate them into a global potential energy surface (PES). The code completely automates all of the steps and procedures that go into fitting various classes of PESs, being well-suited for treating systems with highly-anisotropic interactions, which are traditionally challenging for other fitting approaches.

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The program is designed to run in parallel on Linux-based machines ranging from small workstations to large high-performance computing clusters, and does not require a significant amount of human intervention for functioning: once the PES-construction process has started, all aspects of the potential development were designed to work reliably for a broad range of systems with no human supervision. The fitting algorithms implemented in the code are based on the L-IMLS methodology, and have many advanced features such as options for data-point placement, flexibility to include gradients in the fit, and iterative refinement. The niche of these algorithms is to obtain an interpolative representation of high-level electronic energies with negligible (arbitrarily small) fitting error, requiring minimal human supervision in the entire process of selection, computation, and fitting of the ab initio data. Other features incorporated into the program include: efficient use of large scale parallelization (including load balancing and detailed node-performance analysis); a unified massively parallel subroutine that calls the electronic-structure codes; a restart and backup strategy that permits a full recovery if the calculation is interrupted; a set of output files that allow the user to follow every detail of the PES-development; and a final detailed-report of errors to evaluate the quality of the PES. The code is designed to be as black-box and user-friendly as possible. Most of the required parameters are set to sensible defaults and examples and tutorials are available. A single input file specifies all relevant information concerning the system and the fitting strategy. The code will automatically identify the system symmetry, which is both respected in the fit and exploited to reduce the number of data points needed. Using our methodology, which has no fundamental conceptual limitations, the final PES can be always improved in different ranges of energies (globally, or in specific ranges of coordinates) up to any desired accuracy. The ultimate goal is to represent the computed ab initio data with such high-fidelity, that when used in theoretical studies the results directly reflect the underlying level of the ab initio calculations.

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AUTOSURF package is composed of three main programs: AUTOSURF-PES carries out the automated construction of the PES to a user-specified accuracy (starting with a sparse set of initial ab initio seed points, the program grows a fitted PES over predefined ranges of energy and coordinates until the desired level of precision is reached). AUTOSURF-PLOT permits arbitrary evaluations of the constructed PES, the generation of plots of 1D or 2D cuts of the surface (with optional relaxation) for any of the internal variables, and also to perform a variety of fitting error analyses in specified energy and coordinate ranges. A utility program called AUTOSURF-ABI performs guided surveys of the PES (various cuts), facilitates the benchmark of electronic structure methods, and the development of composite schemes such as complete basis set (CBS) extrapolation.

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AUTOSURF-related REFERENCES

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Book Chapter

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R. Dawes and E. Quintas-Sánchez, “The Construction of Ab Initio-Based Potential Energy Surfaces”, in Reviews in Computational Chemistry, eds. A. L. Parrill and K. B. Lipkowitz, Chapter 5, pp 199–264, John Wiley & Sons, DOI: 10.1002/9781119518068.ch5 (2018).

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Articles

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E. Quintas-Sánchez  and  R. Dawes, “AUTOSURF: a Freely Available Program to Construct Potential Energy Surfaces”, Journal of Chemical Information and Modelling 59, 262–271, DOI: 10.1021/acs.jcim.8b00784 (2019).

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B. Desrousseaux, E. Quintas-Sánchez, R. Dawes and F. Lique, “Collisional Excitation of CF+ by H2: Potential Energy Surface and Rotational Cross Sections”, The Journal of Physical Chemistry A, in press, DOI: 10.1021/acs.jpca.9b05538 (2019).

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S. Sur, E. Quintas-Sánchez, S. Ndengué and R. Dawes, “Development of a potential energy surface for the O3-Ar system: rovibrational states of the complex”, Physical Chemistry Chemical Physics 21, 9168–9180, DOI: 10.1039/c9cp01044k (2019).

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A. Faure, P. Dagdigian, C. Rist, R. Dawes, E. Quintas-Sánchez, F. Lique and M. Hochlaf, “Interaction of Chiral Propylene Oxide (CH3CHCH2O) with Helium: Potential Energy Surface and Scattering Calculations”, ACS Earth and Space Chemistry 3, 964–972, DOI: 10.1021/acsearthspacechem.9b00069 (2019)

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C. Bop, F. Batista-Romero, A. Faure, E. Quintas-Sánchez, R. Dawes, and F. Lique, “Isomerism Effects in the Collisional Excitation of Cyanoacetylene by Molecular Hydrogen”, ACS Earth and Space Chemistry 3, 1151–1157, DOI: 10.1021/acsearthspacechem.9b00049 (2019).

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E. Castro-Juárez, X.-G. Wang, T. Carrington Jr., E. Quintas-Sánchez and R. Dawes, “Computational
Study of the Ro-Vibrational Spectrum of CO-CO2”, The Journal of Chemical Physics 151, 084307,
DOI: 10.1063/1.5119762 (2019).

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