The primary objective of creating the CAESAR package was to make its programs menu-driven
to such an extent that one can use the package to generate useful results even without extensive
knowledge in crystallography, electronic structure theory and computer programming. Another
objective was to make the running of its programs as real-time as possible. The CAESAR package can
be a useful research tool for those who look for qualitative structure-property relationships to be tested
and refined by further experiments. It can also be a useful teaching tool for undergraduate and graduate
courses on molecular orbital theory, inorganic chemistry and solid state chemistry.
We discuss the strengths and weaknesses of extended Hückel electronic structure calculations in
pages redirected by proper links beloe. We show how to install and run the CAESAR package and described the use of the crystal
structure analysis and editing program. We summarize essential aspects of
molecular and solid state electronic structure theories to provide the users with a clear
picture about the kinds of computational results the programs of the CAESAR package produce. The
use of the molecular orbital calculation and analysis programs is presented too, including
electronic band structure calculation and analysis programs and the Fermi
surface calculation and analysis programs as well as the electron density calculation and
analysis programs. A number of examples are included Gallery to help the
users acquire some feel as to how the CAESAR package can be employed in solving their own research
problems. It is hoped that this website will serve as a useful source for the CAESAR package as well as a hands-on
guide for learning how to think about structures and properties of molecules, solids and surfaces.
We would like to acknowledge those whose work we incorporated in producing the current
CAESAR package by briefly tracing the important developments leading to the package. R. Hoffmann
devised the extended Hückel method for molecular electronic structure calculations 1 and wrote the
first program for such calculations.2 This program was improved by J. Howell, A. Rossi, D. Wallace
and K. Haraki in R. Hoffmann’s laboratory.3 Based on this work, M.-H. Whangbo wrote the first
extended Hückel program for electronic band structure calculations for solids at R. Hoffmann’s
laboratory in 1976.4,5 This program was improved by T. Hughbanks, M. Kertesz, S. Wijeyesekera, C.
Wilker and C. Zheng at R. Hoffmann’s laboratory.6-9 At M.-H. Whangbo’s laboratory M. Evain
revised and reorganized the program further and added crystal structure analysis and Fermi surface
calculation programs in 1987. A few of the programs revised by M. Evain were released to QCPE.10
1. Hoffmann, R., J. Chem. Phys. 1963, 39, 1397.
2. Hoffmann, R., QCPE 1964, 11, 30.
3. Howell, J.; Rossi, A.; Wallace, D.; Haraki, K.; Hoffmann, R., QCPE 1977, 11, 344.
4. Whangbo, M.-H.; Hoffmann, R., J. Am. Chem. Soc. 1978, 100, 6093.
5. Whangbo, M.-H.; Hoffmann, R.; Woodward, R. B., Proc. Roy. Soc., London, Ser. A, 1979, 366, 23.
6. Hughbanks, T.; Hoffmann, R. J. Am. Chem. Soc. 1983, 105, 3528.
7. Wiejeyesekera, S. D.; Hoffmann, R., Organometallics 1984, 3, 949.
8. Kertesz,M.; Hoffmann, R., J. Am. Chem. Soc. 1984, 106, 3453.
9. Hoffmann, R.; Zheng, C., J. Phys. Chem. 1985, 89, 4175.
10. Whangbo, M.-H.; Evain, M.; Hughbanks, T.; Kertesz, M.; Wijeyesekera, S.; Wilker, C.; Zheng, C.; Hoffmann, R., QCPE 1987, 11, 571.