Targeted excited state algorithms
To overcome the limitations of the traditional state-averaging approaches in excited state calculations, where one solves and represents all states between the ground state and excited state of interest, we have investigated a number of new excited state algorithms. Building on the work of van der Vorst and Sleijpen [SIAM J. Matrix Anal. Appl. 17, 401 (1996)], we have implemented harmonic Davidson and state-averaged harmonic Davidson algorithms within the context of the density matrix renormalization group (DMRG). We have assessed their accuracy and stability of convergence in complete-active-space DMRG calculations on the low-lying excited states in the acenes ranging from naphthalene to pentacene. We find that both algorithms offer increased accuracy over the traditional state-averaged Davidson approach, and, in particular, the state-averaged harmonic Davidson algorithm offers an optimal combination of accuracy and stability in convergence.
© 2007 American Institute of Physics. Received 20 April 2007; accepted 10 July 2007; published online 28 August 2007 One of the authors (J.H.) is funded by a Kekulé Fellowship of the Fond der Chemischen Industrie (Fund of the German Chemical Industry). Another author (G.K.C.) acknowledges support from Cornell University, Cornell Center for Materials Research, the David and Lucile Packard Foundation in Science and Engineering, and the National Science Foundation CAREER program (No. CHE-0645380).
Accepted Version - 0707.3121.pdf
Published - 1_2E2768360.pdf