Example: Relativistic ZORA TS search: CH4 + HgCl2 <==> CH3HgCl + HCl¶
A ZORA scalar relativistic Transition State calculation.
$ADFBIN/adf << eor TITLE Transition State: CH4 + HgCl2 <==> CH3HgCl + HCl noprint sfo,frag print atdist GEOMETRY TransitionState END TSRC DIST 1 5 1.0 END Relativistic scalar ZORA Basis Type TZP Core small Cl TZP/Cl.2p End ATOMS C 0.049484 0.042994 0.000000 H -0.068980 0.638928 -0.915972 H -0.068980 0.638928 0.915972 H -0.841513 -0.626342 0.000000 H 0.555494 -1.148227 0.000000 Hg 2.303289 -0.007233 0.000000 Cl 4.429752 0.776056 0.000000 Cl 1.342057 -2.676083 0.000000 END endinput eor
For the density-functional the Local Density approximation is used (no GGA corrections).
At each geometry cycle the interatomic distance matrix is printed (print atdist).
The initial geometry is a reasonable but not very accurate estimate of the Transition State. The program needs quite a few cycles to converge, which is rather typical for TS searches: they are a lot more tricky and fail more often than a simple minimization. The TSRC key is used to specify a reaction coordinate along which the transition state is sought for. This feature is especially useful when an accurate Hessian is not available.