      real function atweit (iz)                                         ATWE001
c ----------------------------------------------------------------------ATWE002
c     returns atomic weight of atomic symbol ityp, 0 if not found       ATWE003
c ----------------------------------------------------------------------ATWE004
c     This program module is part of the PhysiSoft X-ray Library        ATWE005
c     and may not be sold or reproduced for commercial purposes.        ATWE006
c     Although it has been tested carefully, there is no warranty       ATWE007
c     regarding accuracy or freedom from side-effects.                  ATWE008
c                   (C) 1986-1990 Bernhard Rupp                         ATWE009
c ----------------------------------------------------------------------ATWE010
      parameter (nel=105)                                               ATWE011
                                                                        ATWE012
      real*4 atw(nel)                                                   ATWE013
c --- nel regular elements ---                                          ATWE014
      data(atw(k),k=1,nel)/1.00798,4.002602,6.941,9.012182,10.811,      ATWE015
     & 12.011,14.00678,15.9994,18.9984032,20.1797,22.989768,24.3050,    ATWE016
     & 26.981539,28.0855,30.973762,32.066,35.4527,39.948,39.0983,       ATWE017
     & 40.078,44.955910,47.88,50.9415,51.9961,54.93805,55.847,          ATWE018
     & 58.93320,58.69,63.546,65.39,69.723,72.61,74.92159,78.96,         ATWE019
     & 79.904,83.80,85.4678,87.62,88.90585,91.224,92.90638,95.94,       ATWE020
     & 98.9063,101.07,102.90550,106.42,107.8682,112.411,114.82,         ATWE021
     & 118.710,121.75,127.60,126.90447,131.29,132.90543,137.327,        ATWE022
     & 138.9055,140.115,140.90765,144.24,146.9151,150.36,151.965,       ATWE023
     & 157.25,158.92534,162.50,164.93032,167.26,168.93421,173.04,       ATWE024
     & 174.967,178.49,180.9479,183.85,186.207,190.2,192.22,195.08,      ATWE025
     & 196.96654,200.59,204.3833,207.2,208.98037,208.9824,209.9871,     ATWE026
     & 222.0176,223.0197,226.0254,227.0278,232.0381,231.0359,238.0289,  ATWE027
     & 237.0482,244.0642,243.0614,247.0703,247.0703,251.0796,252.0829,  ATWE028
     & 257.0951,258.0986,259.1009,260.1053,261.1087,262.1138/           ATWE029
                                                                        ATWE030
      atweit=atw(iz)                                                    ATWE031
      if (iz.lt.1.or.iz.gt.105) atweit=0.0                              ATWE032
      return                                                            ATWE033
      end                                                               ATWE034
                                                                        ATWE035
                                                                        ATWE036
                                                                        ATWE037
