Linear Response Function of Bond-Order

• Main Authors: Nayuta Suzuki, Yuki Mitsuta, Mitsutaka Okumura, Shusuke Yamanaka
• Format: Article
• Language: English
• Published: MDPI AG 2016-10-01
• Series: International Journal of Molecular Sciences
• Subjects: linear response function; bond order; acid dissociation reaction
• Online Access: http://www.mdpi.com/1422-0067/17/11/1779

We present the linear response function of bond-orders (LRF-BO) based on a real space integration scheme for molecular systems. As in the case of the LRF of density, the LRF-BO is defined as the response of the bond order of the molecule for the virtual perturbation. Our calculations show that the LRF-BO enables us not only to detect inductive and resonating effects of conjugating systems, but also to predict pKa values on substitution groups via linear relationships between the Hammett constants and the LRF-BO values for meta- and para-substituted benzoic acids. More importantly, the LRF-BO values for the O-H bonds strongly depend on the sites to which the virtual perturbation is applied, implying that the LRF-BO values include essential information about reaction mechanism of the acid-dissociation of substituted benzoic acids.