TY - JOUR
T1 - The dominant one- and two-photon excited states in the nonlinear optical response of octatetraene
T2 - Ab initio versus semiempirical theoretical descriptions
AU - Beljonne, D.
AU - Shuai, Z.
AU - Serrano-Andrés, L.
AU - Brédas, J. L.
N1 - Funding Information:
This work is supported by the Belgian Prime Minister Federal Services for Scientific, Technical, and Cultural Affairs (Interuniversity Attraction Pole
PY - 1997/11/7
Y1 - 1997/11/7
N2 - The one- and two-photon singlet excited states, relevant for the description of the nonlinear optical response of the octatetraene molecule, have been characterized by the ab initio complete active space self-consistent-field/multiconfiguration second-order perturbation theory (CASSCF/CASPT2) technique. We compare the nature of the main electronic couplings among excited states, as obtained at the ab initio level, to that provided by the semiempirical Pariser-Parr-Pople (PPP) method. Both approaches indicate the presence of a dominant Ag excited state at about 1.6 times the optical gap. However, in contrast to the PPP results, other two-photon states are found in the ab initio calculations to contribute significantly to the cubic polarizability.
AB - The one- and two-photon singlet excited states, relevant for the description of the nonlinear optical response of the octatetraene molecule, have been characterized by the ab initio complete active space self-consistent-field/multiconfiguration second-order perturbation theory (CASSCF/CASPT2) technique. We compare the nature of the main electronic couplings among excited states, as obtained at the ab initio level, to that provided by the semiempirical Pariser-Parr-Pople (PPP) method. Both approaches indicate the presence of a dominant Ag excited state at about 1.6 times the optical gap. However, in contrast to the PPP results, other two-photon states are found in the ab initio calculations to contribute significantly to the cubic polarizability.
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U2 - 10.1016/S0009-2614(97)00958-5
DO - 10.1016/S0009-2614(97)00958-5
M3 - Article
AN - SCOPUS:0031558689
SN - 0009-2614
VL - 279
SP - 1
EP - 8
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 1-2
ER -