Try Again

Next: Optimize the Geometry Up: Run a Basic Calculation Previous: Monitor the Output

Try Again

1.

Finally . . . be sure to change to START=F in your h2co.cntl file to tell the program to read the previous settings, which are stored in the h2co.rstrt, rather than starting from scratch again. Refer to Figure 7. Run it again and we have a converged system for formaldehyde with a total energy of -22.537 H.

2.

Look at energy convergence with paw_show.

alpha:~/tutorial/h2co> paw_show -e h2co

**Figure:** *Sample output from paw_show (after scaling) for formaldehyde, with static energy (H) vs time (psec).*
$\begin{figure}\begin{center} \begin{picture} (300,200) \put(0,0){\special{psfil... ...AW_tutorial/show.eps hscale=50 vscale=50}} \end{picture}\end{center}\end{figure}$

This program uses the X-windows plotting program xmgr. It will plot the energy as a function of the time (there are also other stats it can plot; evoke it with the -h option to find out more). See Figure 6. You may be able to see the jumps in energy as we switch friction. Ideally, we want an energy without friction. So, if your energy is not yet converged to your satisfaction, you can always run it again (maybe with more timesteps and/or less friction) until you can see it with paw_show.

**Figure:** *h2co.cntl (3)*
$\begin{figure}\begin{small} \begin{tex2html_preform}\begin{verbatim}!CONTROL !G... ... !END !END !END !EOB\end{verbatim}\end{tex2html_preform}\end{small}\end{figure}$

Next: Optimize the Geometry Up: Run a Basic Calculation Previous: Monitor the Output

Wun Chiou
2000-03-30