We investigate the feasibility of high-performance scientific computation using cloud computing resources, as an alternative to traditional resources. The availability of large, virtualized pools of computational resources raises the possibility of a new, advantageous compute paradigm for scientific research. To achieve this, we have developed a set of tools which make the cloud platform behave virtually like a local homogeneous computer cluster. We show that for research groups who do not need advanced network performance, cloud computing can provide convenient access to reliable, high-performance clusters, without the need to purchase and maintain or even understand sophisticated hardware and high-performance computational methods. For developers, cloud virtualization allows scientific codes to be optimized and pre-installed, facilitating control over the computational environment. Preliminary tests are presented for serial and parallelized versions of the widely used x-ray spectroscopy and electronic structure code FEFF on the Amazon elastic compute cloud, including CPU and network performance.