[molpro-user] Discrepancy in energy values

[Susi Lehtola]

On 01/07/2017 10:20 PM, Bhargava Anusuri wrote:
> Dear users,
>                 I am computing potential energy surface of CCH+ using
> Molpro. I have observed that there is a difference in energy values for
> the same geometry when it was computed in a loop and when it is computed
> separately as a single point.
>
> r(C-H) = 2.4 a.u , r(C-C) = 21.9 a.u, C-C-H angle = 179 degree :
> -75.74572157 hartree (Single point)
> -75.78211095 hartree (in a loop)

The single point is probably converging onto a saddle point solution. 
Rerun with stability analysis and you should get the lower energy.

-- 
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Mr. Susi Lehtola, PhD             Chemist Postdoctoral Fellow
susi.lehtola at alumni.helsinki.fi   Lawrence Berkeley National Laboratory
http://www.helsinki.fi/~jzlehtol  USA
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