Harnessing molecular excited states with Lanczos chains


Baroni S., Gebauer R., Malcioglu O. B. , Saad Y., Umari P., Xian J.

JOURNAL OF PHYSICS-CONDENSED MATTER, cilt.22, 2010 (SCI İndekslerine Giren Dergi) identifier identifier identifier

Özet

The recursion method of Haydock, Heine and Kelly is a powerful tool for calculating diagonal matrix elements of the resolvent of quantum-mechanical Hamiltonian operators by elegantly expressing them in terms of continued fractions. In this paper we extend the recursion method to off-diagonal matrix elements of general (possibly non-Hermitian) operators and apply it to the simulation of molecular optical absorption and photoemission spectra within time-dependent density-functional and many-body perturbation theories, respectively. This method is demonstrated with a couple of applications to the optical absorption and photoemission spectra of the caffeine molecule.