function lta_density,wts,wtn,t

;----------------------------------------------------------
;
; Purpose:
;   This is the formulation of Luo et al., GRL, 1997 
;   for determining the solution density of 
;   liquid ternary h2o/hno3/h2so4 aerosols (LTA).   
;  
;   It will return the binary solution density for either h2o-h2so4
;   or h2o-hno3,  by setting the appropriate wt fraction=0>
;
; Input:
;   t   = temperature in K
;   wts = wt. fraction h2so4 in solution 
;   wtn = wt. fraction hno3 in solution
;
; Output:
;   result = solution density, g/cm3
;
; Source: Mark Hervig
;
;----------------------------------------------------------

   x=[2.393284E-02,-4.359335E-05,7.961181E-08,0.0,-0.198716351,         $
      1.39564574E-03,-2.020633E-06,0.51684706,-3.0539E-03,4.505475E-06, $
      -0.30119511,1.840408E-03,-2.7221253742E-06,-0.11331674116,        $ 
      8.47763E-04,-1.22336185E-06,0.3455282,-2.2111E-03,3.503768245E-06,$
      -0.2315332,1.60074E-03,-2.5827835E-06]

      w   = wts+wtn
      wth = 1.-w
      v1  = x(0) +x(1) *T +x(2) *T^2 +x(3)*T^3
      vs  = x(4) +x(5) *T +x(6) *T^2 +(x(7)+x(8)*T+x(9)*T^2)*w $
            +(x(10) +x(11) *T +x(12) *T^2) *w *w
      vn  = x(13) +x(14) *T +x(15) * T^2 +(x(16) +x(17) *T +x(18) *T^2) *w $
            +(x(19) +x(20) *T +x(21) *T^2) *w *w
      vmcal = v1*wth/18.016 + vs*wts/98.08 + vn*wtn/63.016

      result = 1/vmcal/1000. ; g/cm3

      return,result
      end