Determination of energy minima and saddle points using multireference configuration interaction methods in combination with reduced gradient following: The S0 surface of H2CO and the T1 and T2 surfaces of acetylene
✍ Scribed by Michal Dallos; Hans Lischka; Elizete Ventura Do Monte; Michael Hirsch; Wolfgang Quapp
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 120 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
The implementation of the reduced gradient following (RGF) method into the COLUMBUS quantum-chemical program system is reported using the newly developed analytic MR-CISD/AQCC gradient feature. By this combination a very useful tool has been developed for general searches of stationary points on ground- and excited-state energy surfaces. This procedure is applied to the S(0) surface of H(2)CO and the T(1) and T(2) surfaces of acetylene. For H(2)CO we investigated three minima (formaldehyde, s-trans, and s-cis hydroxycarbene) and five saddle points. For the T(1) and T(2) states of acetylene the cis- and trans-minima and the planar and nonplanar saddle points were computed.