On the use of the Laplace transform in local correlation methods

The applicability of the Laplace transform ansatz of Almlof in the context of local correlation methods with a priori restricted sets of wavefunction parameters is explored. A new local MP2 method based on the Laplace transform ansatz is described, its relation to the local MP2 method based on the Pulay ansatz is elucidated, and its accuracy and efficiency are compared to the latter.