Central moments in quantum chemistry

AbstractWe define central moments of operators on finite‐dimensional vector spaces and study some of their basic aspects. Central moments may be viewed as generalizations of the dispersion of a Hermitian operator. We show how eigenvalues may be represented by central moments, and how central moments may be used to obtain Krylov subspace approximations for operators on inner product spaces. We show that central‐moments approximations are compatible with the concepts of size‐consistency in quantum chemistry, and we use this to suggest a foundation for central‐moments approximations in Coupled Cluster theory. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008