Clark, R.E.H., Cowan, R.D., & Bobrowicz, F.W. 
1986, Atomic Data Nucl. Data Tables, 34, 415.
Isoelectronic sequence fits to configuration-averaged
photoionization cross sections and ionization energies.

Byte-per-byte description of file: clark1.dat (144 records)
Fit parameters for calculation of ionization energies
-------------------------------------------------------------------------------
   Bytes Format  Units   Label   Explanations
-------------------------------------------------------------------------------
   1-  2  I2     ---     IS      Number of electrons (isoelectronic sequence)
   4-  4  I1     ---     n       Principal quantum number of the shell 
   6-  6  I1     ---     l       Orbital quantum number of the subshell 
   8- 18  E11.4  ---     A1      Fit parameter
  20- 30  E11.4  ---     A2      Fit parameter
  32- 42  E11.4  ---     A3      Fit parameter
  44- 54  E11.4  ---     A4      Fit parameter
  56- 66  E11.4  ---     A5      Fit parameter
-------------------------------------------------------------------------------
Note: Fit parameters are listed here for the excited subshells only.

Byte-per-byte description of file: clark2.dat (144 records)
Fit parameters for calculation of photoionization cross sections
-------------------------------------------------------------------------------
   Bytes Format  Units   Label   Explanations
-------------------------------------------------------------------------------
   1-  2  I2     ---     IS      Number of electrons (isoelectronic sequence)
   4-  4  I1     ---     n       Principal quantum number of the shell 
   6-  6  I1     ---     l       Orbital quantum number of the subshell 
   8-  9  I2     ---     IP      Fit parameter
  11- 11  I1     ---     N       Fit parameter
  13- 23  E11.4  ---     B1      Fit parameter
  25- 35  E11.4  ---     D1      Fit parameter
  37- 47  E11.4  ---     B2      Fit parameter
  49- 59  E11.4  ---     D2      Fit parameter
  61- 71  E11.4  ---     C1      Fit parameter
  73- 83  E11.4  ---     C2      Fit parameter
  85- 95  E11.4  ---     C3      Fit parameter
  97-107  E11.4  ---     C4      Fit parameter
-------------------------------------------------------------------------------
Note: Fit parameters are listed here for the excited subshells only.