We present the SLIMP package, which provides an efficient way for the calculation of strong-field ionization rate and high-order harmonic spectra based on the single active electron approximation. The initial states are taken as single-particle orbitals directly from output files of the general purpose quantum chemistry programs GAMESS, Firefly and Gaussian. For ionization, the molecular Ammosov–Delone–Krainov theory, and both the length gauge and velocity gauge Keldysh–Faisal–Reiss theories are implemented, while the Lewenstein model is used for harmonic spectra. Furthermore, it is also efficient for the evaluation of orbital coordinates wavefunction, momentum wavefunction, orbital dipole moment and calculation of orbital integrations. This package can be applied to quite large basis sets and complex molecules with many atoms, and is implemented to allow easy extensions for additional capabilities. Program summaryProgram title: SLIMPCatalogue identifier: AEWE_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEWE_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 90277No. of bytes in distributed program, including test data, etc.: 927942Distribution format: tar.gzProgramming language: Fortran 90.Computer: All computers with a Fortran compiler supporting at least Fortran 90.Operating system: All operating systems with such a compiler. The makefile depends on a Unix-like system and needs modification under Windows.RAM: Memory requirement depends on the size of the molecules and the number of basis functions. For instance, about 2.8MB RAM is required for N2 molecules with the acc-pvqz basis set (210 basis functions). However, the SF6 molecules require 22MB RAM with the same basis set (739 basis functions).Classification: 16.1, 16.10, 2.7.Nature of problem: In modeling of atoms and molecules subjected to intense laser pulses, there is a general need for the calculation of theoretical models. However, the application of these models requires the effective evaluation of orbital coordinates wavefunction, momentum wavefunction, orbital dipole moment or calculation of orbital integrations. This package provides an efficient way for these calculations directly from the output files of the widely used GAMESS, Firefly and Gaussian programs.Solution method: The molecular orbital is constructed from a linear combination of atomic orbitals, which is further expanded with Cartesian gaussian type orbitals (GTO). The orbital momentum wavefunction and dipole moment can be constructed with the Fourier transformed GTOs. Orbital integrations rely on the elementary integrations of GTOs. These results are used directly as input in the subsequent models calculations.Restrictions: Current implementation supports the S, P L, D, F and G types, of GTOs. Here L indicates the diffuse basis. However, the extension to higher order basis is straight-forward. This package supports the versions of GAMESS (US, 2013), Firefly (8.1), and Gaussian (both 09 and 03). For older versions, mild modifications on the reading formats may be necessary in the modules.Running time: The running time depends on the size of the molecules, the number of basis functions, and most importantly, on the problem to which this package has been employed. Typically for a single-processor PC-type computer it can vary between a few seconds and days.
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