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Manuscript Title: A computer program for the calculation of electron scattering and photoionization cross sections of atomic systems with configuration (np)q. See erratum Comp. Phys. Commun. 1(1970)470.
Authors: M.J. Conneely, L. Lipsky, K. Smith, P.G. Burke, R.J.W. Henry
Program title: ATOMNP
Catalogue identifier: AAIA_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 1(1970)306
Programming language: Fortran.
Computer: IBM 360/65.
Operating system: OS 360.
Program overlaid: yes
RAM: 31K words
Word size: 64
Peripherals: magnetic tape.
Keywords: Atomic physics, Scattering, Close-coupling, Photoionization, Cross-section, Electron atom, Coupled Differential equation, Numerov, Fractional Parentage coefficient, Clebsch-gordan Coefficient, Racah coefficient, Transition, Continuum Hartree-fock.
Classification: 2.4.

Nature of problem:
This program allows one to study the scattering of an electron by an atom or ion with configuration (np)**q, where n=2 or 3, and q can take all values between 0 and 6, under the assumption that all the ground state trms are "closely coupled", but no excited terms contribute.

Unusual features:
To obtain sufficient accuracy for numerical stability double precision is required on the IBM 360 series. This has not been necessary when using machines with 36 bit words.

Running time:
The time required depends on N, the number of equations, and on NE, the number of exchange terms. For electron-carbon scattering with N=2, NE= 7 (L=0, S=1/2, Phi=even), the time required on the IBM 360/65 is 0.96 minutes. For the case L=2, S=1/2, Phi=even, we have N=5, NE=19 and the time required is 5.05 minutes.