TY - JOUR
T1 - Structure and nonlinear electrical properties of squaric acid derivatives
T2 - A theoretical study of the conformation and deprotonation effects
AU - Spassova, M.
AU - Kolev, T.
AU - Kanev, I.
AU - Jacquemin, D.
AU - Champagne, B.
PY - 2000/8/25
Y1 - 2000/8/25
N2 - The molecular structure and nonlinear electrical properties of the three squaric acid conformers (Z, Z), (Z, E) and (E, E) and of their singly deprotonated form, the monohydrogenosquarate anion, are reported. The structures are optimized at the second-order Moller-Plesset (MP2) perturbational theory level by using the 6-311G(**) basis set supplemented by a set of diffuse p and d functions. The (Z, Z) conformer is more stable by 2(8) kcal/mol than the (Z, E) ((E, E)) conformer. The finite field procedure applied at the same level shows that, in the static limit, the electronic first hyperpolarizability of the anion is 40% smaller than those of the three squaric acid conformers whereas its second hyperpolarizability is more than twice as large. The origin of the first hyperpolarizability of the (Z, Z) conformer is explained by adopting the missing state analysis at the single CI level. (C) 2000 Elsevier Science B.V.
AB - The molecular structure and nonlinear electrical properties of the three squaric acid conformers (Z, Z), (Z, E) and (E, E) and of their singly deprotonated form, the monohydrogenosquarate anion, are reported. The structures are optimized at the second-order Moller-Plesset (MP2) perturbational theory level by using the 6-311G(**) basis set supplemented by a set of diffuse p and d functions. The (Z, Z) conformer is more stable by 2(8) kcal/mol than the (Z, E) ((E, E)) conformer. The finite field procedure applied at the same level shows that, in the static limit, the electronic first hyperpolarizability of the anion is 40% smaller than those of the three squaric acid conformers whereas its second hyperpolarizability is more than twice as large. The origin of the first hyperpolarizability of the (Z, Z) conformer is explained by adopting the missing state analysis at the single CI level. (C) 2000 Elsevier Science B.V.
KW - Configuration interaction singles
KW - Deprotonation effects
KW - Hyperpolarizability
KW - Moller-plesset
KW - Squaric acid
UR - http://www.scopus.com/inward/record.url?scp=0034714069&partnerID=8YFLogxK
U2 - 10.1016/S0166-1280(99)00473-X
DO - 10.1016/S0166-1280(99)00473-X
M3 - Article
AN - SCOPUS:0034714069
SN - 0166-1280
VL - 528
SP - 151
EP - 159
JO - Journal of Molecular Structure: THEOCHEM
JF - Journal of Molecular Structure: THEOCHEM
ER -