Pairing in the Woods-Saxon Codes

The following values of IMODEL may be used:

The initial values and are calculated at zero frequency and may be kept fixed at these values. Alternatively, may be recalculated at each step in the calculation to reproduce the correct particle number (IMODEL = 1 or 3). Similarly, the pairing may be treated self-consistently (IMODEL = 3), or modified (IMODEL = 1 or 2). For plotting quasiparticle levels, use only IMODEL=0 or IMODEL=2, otherwise discontinuities may arise when the vacuum changes (going from 0 to 2 quasiparticle states). The following values of DELTA0 may be used to modify the pairing:

i.e. a positive DELTA0 is a multiplication factor for the pairing calculated at zero frequency, while if a negative value is specified, the absolute value (in MeV) is taken as the pairing. The decreasing pairing with frequency, (DELTA0=0), is modelled by:

The critical frequency (OMCRIT), where the pairing has fallen to 50% of its initial value, is usually taken as =0.70 MeV/.

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