No CrossRef data available.
Published online by Cambridge University Press: 16 February 2011
Quantum Many-electron calculations based on Multiple-excited configuration interaction have been implemented on squaraine Molecules. It is found that certain squaraines possess negative third order optical susceptibilities (γ) even in the zero frequency limit. Our calculations agree well with the experimental results obtained by Dirk and co-workers[1] for anilinium squarylium (BSQ) in terms of the sign and Magnitude. High-lying two-photon states in squaraines are found to be always critically important. The sign of γ is found to depend on the electron donating ability of the two side groups in squaraines.