ABSTRACT:A general formula has been established for the expansion of the product of two normalized associated Legendre functions centered on the nuclei a and b. This formula has been utilized for the evaluation of two-center overlap and nuclear attraction integrals over Slater-type orbitals (STOs) with integer and noninteger principal quantum numbers. The formulas given in this study for the evaluation of two-center overlap and nuclear attraction integrals show good rate of convergence and great numerical stability under wide range of quantum numbers, orbital exponents, and internuclear distances.

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As an example of the use of the analytical formulas derived for electric multipole moment integrals over STOs in our previous work (I.I. Guseinov, et al., J. Mol. Struct. (Theochem) 465 (1999) 5), the -pole electric moments have been calculated for the ground electronic states of LiH, BH and FH of the first-row diatomic hydride molecules. Calculated electric multipole moment values are in agreement with literatures. By the use of these analytical formulas the -pole moments for multiatomic molecules can be evaluated most efficiently and accurately by employing STOs as basis sets.

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The recurrence relations are presented for the calculation of basic overlap integrals, by making use of which other overlap integrals are calculated analytically. These recurrence relations are especially useful for the calculation of any overlap integral for large quantum numbers. For the arbitrary values of screening constants of atomic orbitals and internuclear distances an accuracy of the computer results is satisfactory for the values of principal quantum numbers of Slater functions up to 50.

The reaction kinetics of CO 2 absorption into new carbon dioxide binding organic liquids (CO 2 BOLs) was comprehensively studied to evaluate their potential for CO 2 removal. A stopped-flow apparatus with conductivity detection was used to determine the CO 2 absorption kinetics of novel CO 2 BOLs composed of DBN (1,.0]non-5ene)/1-propanol and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene)/1-butanol. A modified termolecular reaction mechanism for the reaction of CO 2 with CO 2 BOLs was used to calculate the observed pseudo-first-order rate constant k 0 (s −1 ) and second-order reaction rate constant k 2 (m 3 /kmol.s). Experiments were performed by varying organic base (DBN or TBD) weight percentage in alcohol medium for a temperature range of 288-308 K. It was found that k 0 increased with increasing amine concentration and temperature. By comparing using two different CO 2 BOL systems, it was observed that the TBD/1-butanol system has faster reaction kinetics than the DBN/1-propanol system. Finally, experimental and theoretical activation energies of these CO 2 BOL systems were obtained and compared. Quantum chemical calculations using spin restricted B3LYP and MP2 methods were utilized to reveal the structural and energetic details of the single-step termolecular reaction mechanism.

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