Molecular Orbital Estimation of Reduced Partition Function Ratios of Lithium Interacting with Aromatic Hydrocarbons with Condensed Benzene Rings

2003 ◽  
Vol 58 (5-6) ◽  
pp. 325-332 ◽  
Author(s):  
Takao Oi ◽  
Satoshi Yanase
Keyword(s):  
Partition Function ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Lithium Atom ◽  
Isotope Effects ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Graphene Layers ◽  
Stage Separation ◽  
Benzene Rings

Molecular orbital calculations at the B3LYP/6-311G(d) level were carried out to elucidate the lithium isotope effects accompanying chemical insertion of lithium from 1-methoxybutane solution containing lithium and naphthalene to graphite. The lithium atom between the graphene layers of graphite was modeled as lithium atoms in 1:1 complexes of lithium and simple aromatic hydrocarbons with condensed benzene rings. The 7Li-to-6Li isotopic reduced partition function ratio (RPFR) was found to be a decreasing function of the number of benzene rings adjacent to the benzene ring above which the lithium atom was located, and was “saturated” at 1.04570 at 25 °C. The most plausible lithium species in the 1-methoxybutane solution was a lithium atom interacting with a naphthalene molecule and solvated by a 1-methoxybutane molecule in the contact ion pair manner. Its RPFR value was 1.07126 at 25 °C. The two RPFR values gave a single-stage separation factor of 1.024 for the lithium isotopes, which agreed well with the experimental value of 1.023.

Ab initio Molecular Orbital Calculations of Reduced Partition Function Ratios of Hydrated Lithium Ions in Ion Exchange Systems

2001 ◽  
Vol 56 (3-4) ◽  
pp. 297-306 ◽  
Author(s):  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Partition Function ◽  
Ion Exchange ◽  
Molecular Orbital ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Water Molecules ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Lithium Ions ◽  
Additional Water

Abstract Molecular orbital (MO) calculations at the HF/6-31G(d) level were carried out for the aquolithium ions, Li+(H2O)n (n = 3, 4, 5, 6, 8, 10 and 12) and the aquolithium ions interacting with the methyl sul­fonate ion (MeS-), Li+MeS-(H2O)n (n = 0, 3,4, 5, 6, 7, 8 and 10) which were, respectively, intended to be substitutes for lithium species in the solution and resin phases of ion exchange systems for lithium isotope separation. For each of the species considered, at least one optimized structure with no negative frequency was obtained, and the 7Li-to-6Li isotopic reduced partition function ratio (RPFR) was esti­mated for the optimized structure. The solvation number in the primary solvation sphere was four, both in the solution and resin phases; three waters and MeS" formed the primary solvation sphere in the res­ in phase. Additional water molecules moved off to the secondary solvation sphere. It was found that consideration on the primary solvation sphere alone was insufficient for estimations of reduced parti­tion function ratios of aquolithium ions. Although the agreement between the experimentally obtained lithium isotope fractionation and the calculated results is not satisfactory, it is pointed out that the HF/6-31 G(d) level of the theory is usable for elucidation of lithium isotope effects in aqueous ion exchange systems.

Ab initio Molecular Orbital Calculations of Reduced Partition Function Ratios of Polyboric Acids and Polyborate Anions

2000 ◽  
Vol 55 (6-7) ◽  
pp. 623-628 ◽  
Author(s):  
Takao Oi
Keyword(s):  
Partition Function ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Equilibrium Constants ◽  
Boron Isotope ◽  
Molecular Orbital Calculations ◽  
Exact Evaluation ◽  
Reac Tions

Abstract Molecular orbital calculations at the HF/6-3 lG(d) level were carried out for polyboric acids and poly-borate anions up to a pentamer to estimate their 11B -to-10B isotopic reduced partition function ratios (RPFRs) and examine the additivity of logarithms of RPFRs. Approximate RPFR-values calculated by the use of the additivity agreed with exact RPFR-values within a margin of 1% error. This error was equivalent to a 5% error on ln(RPFR). The equilibrium constants of mono boron isotope exhange reac-tions between three-coordinate boron and four-coordinate boron ranged from 1.0203 to 1.0360 at 25 °C, indicating the importance of exact evaluation of RPFRs of polymers.

Lithium Isotope Effect Accompanying Electrochemical Insertion of Lithium into Liquid Gallium

2010 ◽  
Vol 65 (5) ◽  
pp. 461-467 ◽  
Author(s):  
Keita Zenzai ◽  
Ayaka Yasui ◽  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Isotope Effect ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Ethylene Carbonate ◽  
Quantitative Agreement ◽  
Liquid Gallium ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Mixed Solution ◽  
Separation Factors

Lithium was electrochemically inserted from a 1 : 2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1M LiClO4 into liquid gallium to observe lithium isotope effects accompanying the insertion. It was observed that the lighter isotope 6Li was preferentially fractionated into liquid gallium with the single-stage lithium isotope separation factors S, ranging from 1.005 to 1.031 at 50 °C and 1.003 to 1.024 at 25 °C. The lithium isotope effects estimated by molecular orbital calculations at the B3LYP/6-311G(d) level of theory agreed qualitatively with those of the experiments, but the quantitative agreement of the two was not satisfactory

Simulated ab initio molecular orbital calculations of large polynuclear aromatic hydrocarbons

2009 ◽  
Vol 9 (S2) ◽  
pp. 155-170
Author(s):  
Brian J. Duke ◽  
Deidre R. Eilers ◽  
James E. Eilers ◽  
Sungzong Kang ◽  
A. Liberles ◽  
...  
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Molecular Orbital Calculations
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