C CETAFU    SOURCE    CHAT      05/01/12    21:52:32     5004           
c
      FUNCTION C_ETACONFUNC(VINT)
      IMPLICIT INTEGER(I-N)
      complex*16    vint,c_etaconfunc
      real*8    exm,qaa,pcc,eww,xk1,xk2,etb,exv,xep,paa,cco,
     .          exl,xnn,aaa,bbb
      common /MRScone/ exm,qaa,pcc,eww,xk1,xk2,etb,exv,xep,paa,cco,
     .                 exl,xnn,aaa,bbb
      if (exv.lt.0.D0) then
        c_etaconfunc=aaa*(xk1)**(1.D0/abs(exv))
      else
        c_etaconfunc=aaa*exp(-bbb*vint)*(xk1+vint)**(1.D0/exv)+
     .             xk2*etb*vint/(xep+vint)
      endif
      return
      end