Lithium Hydride molecule (ab initio and Kimball)

The total density of the groundstate of the LiH molecule has been computed with GAMESS (Gaussian98 gives the same result, but a contour drawing program has to be bought separately). The structure and energy are optimized at the RHF/6-311G model chemistry. The density contours were plotted with (slightly improved) Pltorb/Dendif, two accompanying free tools of (free) GAMESS (running under Linux (SuSE 5.2) and X-windows). The total energy -7.984655 in the vibrationless state compares with a Kimball value of -7.985005 hartree. The equatorial planes of the two Kimball spheres are superimposed on the density plot. The lowest contour is 0.01 electron per bohr3/2.-
Watch the electron density sharing between the core and the H-ligand showing a remarkable "covalent" bond contribution for the "ionpair" Li+ / H- .
LiH:
  Final Results of Parameter-Optimization
         RHF/6-311g   Kimball      D %
  Etot   -7.984655   -7.985005   -0.0044
  Re      1.605600    1.605630    0.0019
  Vne   -20.419674  -20.423953   -0.021
  Vee     3.468685    3.465214   -0.10
  
  Parameters determined: (-V/T = 2.0000000)
  k1 = 1.02897160  k2 = 1.23924503  
  s1 = 0.27885572  s2 = 0.29125954
  Kimball radii (bohr):
   P(Li 1s2)     Q(LiH)   R(eccentr.of H+)
   0.5630405   2.0221093   0.4490507

  Find Minimum of
  2.25*k1/P2 - 9/P + 2.25*k2/Q2 - 2/(P+Q) +
    1/(P+Q+R) - (3 - (R/Q)2)/Q + 3*s1/P +
    3*s2/Q
  gives the above Etot, and P,Q,R, from which
  Re, Vne, and Vee are computed.

  Parameter-Optimization with G2 Theory
          G2/6-311g   Kimball     D %
  Etot   -8.022475   -8.022485   -0.00012
  Re      1.5946      1.59415    -0.028
  Bond   56.6        56.6         0    kcal/mol
  Parameters determined: (-V/T = 2.0000000)
  k1 = 1.02480344  k2 = 1.23244364  
  s1 = 0.27877144  s2 = 0.28887416
  Kimball radii (bohr):
   P(Li 1s2)     Q(LiH)   R(eccentr.of H+)
   0.5607208   2.0066350   0.44516027

 
Near the two nuclei the isodenses have been cut out in order to prevent the printpaper to be transformed into wet, black pulp.
GamessGaussian 98

Last changes April 26, 2016
This page is from ES.