Command PhIon

Command format

PhIon Energy-1 Energy-2 ...

or

PhIonN Energy-Start Energy-Step Number-of-Energies

This command computes the photoionization or photodetachment dipole matrix elements. The PhIon form does the calculation at a list of scattering energies (in eV). If no energies are present then the energies are taken from the ScatEng, or ScatEngN, data record. The PhIonN form does the calculation at a sequence of scattering energies with fixed spacing (in eV). If the command FileName has been used to define the MatrixElements file, then the final dipole matrix elements are written to that file. Otherwise, the matrix elements are written to a scratch file.

Data records used

• FegeEng, this is the value of the energy parameter (in eV) needed to compute the FEGE local exchange potential.
• ScatEng, photoelectron energy, in eV. This data record is not used if Energy is defined in the command.
• ScatEngN, photoelectron energy, in eV. This data record is not used if Energy is defined in the command.
• ScatContSym, the IR of the continuum orbital.
• EngForm, potential energy formula. This data record can be created using the GenFormPhIon or GenFormScat commands.
• DirProdOvlp, transformation matrix from symmetry adapted wave functions to direct product wave functions. This can be created using the GenFormPhIon or GenFormScat commands.

Optional data records used

• FegeScale, Optional value used to scale the local exchange potential. This can be used to curcumvent singularities in the interative procedure. Default value is 1.0.
• GrnType, Optional, the type of the scattering matrix (1, 0, or -1). Default value is -1 for a Psi^(-) solution.
• IterMax, Optional. Maximum number of iterations allowed in the Pade approximant corrections of the scattering matrix elements. Default value is 15. A value of -1 is used for a static only calculation.
• LMaxEx, Optional. maximum l used in the expansion of 1/r_12 in the exchange terms. Default value is -1, which inclludes all exchange terms.
• NIntReg, number of regions used in stabilization. Default value is 40.
• CnvgKMat, parameter that controls the convergence of the iterative procedure. Default value is 1.0e-6.
• EpsAsym, this data record controls where the asymptotic integration is truncated. The default is to stop the integration when the asymptotic potential is less than CnvgKMat/10 times the asymptotic electron kinetic energy.
• TotalAsymp, controls the form of the asymptotic potential.
• Orthog, this data record controls which orbital groups the continuum function is constrained to be orthogonal to. This overides the orthogonality constraints specified in EngForm.
• RungeKuttaFac this integer controls the step size used in the differential equation integrator. Higher values yields smaller step sizes. Default value is 4.
• HFacWaveAsym, a real number that is used to generate the asymptotic radial grid. The higher the value the more dense the grid will be between for r greater than RMax. Default value is the value of HFacWave used to generate the grid, the default value for that parameter is 10.
• EpsIntError, this is used as an estimate of the error in the numerical integrations. It is used to control the convergenc of the iterative procedure. Default value is 1.0e-8.
• LMaxHomo, contains an integer that specifies the truncation of the partial wave expansion in the homogeneous solution of the static potential scattering. The default value is MAX(LMaxA, LMax/2)
• LMaxK, the maximum l used in the expansion of the homogeneous scattering solution. This is then the maximum l for which dipole matrix elements are computed. Note that this should be greater than or equal to LMaxA. Default value is LMaxA-2.
• NAsymLRange, the range of the functions on the left of the variational expression that should be computed. The default value is to use the full range up to NAsymL.

Examples of use

• test15