title: Determination of energy minima and saddle points using multireference configuration interaction methods in combination with reduced gradient following: the S(0) surface of H(2)CO and the T(1) and T(2) surfaces of acetylene.
abstract: 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.
authors.affiliation: Institute for Theoretical Chemistry and Structural Biology, University of Vienna, Währingerstrasse 17, A-1090 Vienna, Austria.
authors.forename: Michal
authors.initials: M
authors.lastname: Dallos
authors.forename: Hans
authors.initials: H
authors.lastname: Lischka
authors.forename: Elizete
authors.initials: E
authors.lastname: Ventura Do Monte
authors.forename: Michael
authors.initials: M
authors.lastname: Hirsch
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Quapp