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CIOpt

Author/AffiliationBenjamin G. Levine and Todd J. Martinez, University of Illinois
Author emailben@spawn.scs.uiuc.edu
Description of SoftwareCIOpt is a freely downloadable program for the optimization of minimal energy conical intersections (MECIs). It uses the conical intersection optimization scheme described in B. G. Levine, J. D. Coe, and T. J. Martnez, submitted to J. Phys. Chem. A. This method is unique in that it does not require the calculation of nonadiabatic coupling matrix elements. Only energy information is required. This makes this scheme more generally applicable than other conical intersection optimization schemes. Energy gradient information is not required, but if analytic gradients are available they significantly improve convergence. CIOpt does not perform any electronic structure calculations of its own. Instead it can be interfaced with the electronic structure package of the users choice via a template based scheme. When an electronic structure calculation is required CIOpt writes the appropriate input file, calls the electronic structure package, and writes the output. CIOpt includes several advanced features, not available in other software packages. CIOpt contains an algorithm for the optimization of minimal energy intersections of three states (ME3CI). It also contains an algorithm for the optimization of the intersection closest to a reference geometry in weighted Cartesian coordinates (minimal distance conical intersections, or MDCIs). Like the MECI optimization scheme, these schemes do not require nonadiabatic coupling matrix elements. Energy gradient information speeds convergence but is not required.
Submitted2007-09-17
Download software from MCC:CIOpt.tgz (6094 kB)

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Download documentation from:http://cms.mcc.uiuc.edu/wiki/display/st/CIOpt[...]