A Quantum Leap for Desktop Chemistry - C&EN ... - ACS Publications

A Quantum Leap for Desktop Chemistry. Chem. Eng. News , 2001, 79 (5), p 4. DOI: 10.1021/cen-v079n005.p004. Publication Date: January 29, 2001. Copyrig...
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computer-aided chemistry update

AChe

A Quantum Leap for Desktop Chemistry

Excited states in solution The COSMO solvation model has been enhanced to allow modeling of excited state systems in solution, and to speed up calculations. COSMO allows optimization of geometries of solvated systems. CACheMOPAC includes an extensive configuration interaction package allowing a wide range of open- and closed- shell, ground and excited state phenomena to be modeled.

Patented quantum chemistry algorithms in MOPAC 2000 add powerful new capabilities to CAChe, the leading computer-aided chemistry software for experimentalists. Fastest MOPAC 2000's patented linear-scaling Mozyme algorithm provides the same results as conventional MOPAC, but orders of magnitude faster. For example, a full MOPAC energy calculation (SCF) on a 650 atom peptide takes only three minutes on a 650MHz Windows PC. This calculation could not be performed on a desktop computer using conventional quantum mechanical methods.

Transition metals Largest CAChe MOPAC 2000 allows quantum optimizations and property calculations on systems of up to 1,000 atoms on a desktop PC or Macintosh. New algorithms in MOPAC 2000 use a fraction of the memory and CPU

AMI-d adds the capability to optimize geometries of transition metal compounds such as Pt, Ag, Cu, and Fe. AMI-d offers an important advantage in being able to predict heats of formation and other properties with higher accuracy than PM3-tm.

I- , Q. O

400

600

800

Number of Atoms time of conventional quantum mechanics, allowing much larger systems to be run, dramatically faster. MOPAC 2000 offers much larger molecule quantum chemistry capabilities than any other commercial package.

Triplet

Transition State

/ Intersystem \ >/ Crossing \ Points Reactant \ \Singlet Product

MOPAC can model the minimum energy geometry for two degenerate states, for example, a singlet-triplet intersystem crossing. Intersystem crossings have important applications in photography and photochemistry.

Enhanced transition state searching for kinetics

conventional semiempirical : 30 h LJJ

Intersystem crossings

An enhanced SADDLE searching algorithm significantly improves the success rate for the automatic location of transition states.

Higher accuracy MNDO-d improves the accuracy of geometries for some compounds by incorporating d-orbitals. For example, standard MNDO optimizations produce an erroneous flat trigonal structure for the BrF 3 molecule. However, MNDO-d correctly predicts that the "T"-shaped structure is the lowest energy conformation.

What sets CAChe apart? • Award winning property-driven inter- j faces preferred by chemists S Predict any property QSAR, QSPR, statistical analysis • Time saving automation and project management All elements from Hydrogen to Lawrencium Free training movies on each CD Giant molecule quantum chemistry MOPAC 2000

Free downloads at http://www.CACheSoftware.com/free Americas:

CAChe Group, Fujitsu Systems Business of America, Inc. Tel: (1) 503 531 3600 FAX: (1) 503 531 9966 Email: [email protected] URL: http://www.cachesoftware.com

Asia:

Fujitsu Ltd. Japan Tel: (81) 43 299 3681 FAX: (81) 43 299 3019 Email: [email protected]

Europe:

FQS Poland Tel: (4812) 429 43 45 FAX: (4812) 429 61 24 Email: [email protected]

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