  We present an efficient implementation of ground and excited state CCSD
gradients based on Cholesky-decomposed electron repulsion integrals. Cholesky
decomposition, like density-fitting, is an inner projection method, and thus
similar implementation schemes can be applied for both methods. One well-known
advantage of inner projection methods, which we exploit in our implementation,
is that one can avoid storing large V3O and V4 arrays by instead considering
three-index intermediates. Furthermore, our implementation does not require the
formation and storage of Cholesky vector derivatives. The new implementation is
shown to perform well, with less than 10% of the time spent calculating the
gradients in geometry optimizations. The computational time spent per
optimization cycle are furthermore found to be significantly lower compared to
other implementations based on an inner projection method. We illustrate the
capabilities of the implementation by optimizing the geometry of the retinal
molecule (C20H28O) at the CCSD/aug-cc-pVDZ level of theory.
