The polarizability of furan has been investigated using the coupled cl
uster CCS, CC2 and CCSD models. Integral-direct techniques have been a
pplied and calculations containing up to 322 basis functions have been
employed. The results have been compared with experimental data and r
esults of previous calculations. Explicit inclusion of dispersion effe
cts is important for obtaining accurate frequency-dependent polarizabi
lities. (C) 1997 Elsevier Science B.V.