Revisit to Vapor Pressure Isotope Effects of Water Studied by Molecular Orbital Calculations

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.

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H/D Isotope Effects Accompanying Electrolysis of Water as Studied by Molecular Orbital Calculations

Journal of Computer Chemistry Japan ◽

10.2477/jccj.h2302 ◽

2011 ◽

Vol 10 (2) ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

Satoshi YANASE ◽

Takao OI

Keyword(s):

Molecular Orbital ◽

Isotope Effects ◽

Molecular Orbital Calculations

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Dynamics of molecular hydrogen elimination from the methaniminium cation, [CH2NH2]+. Isotope effects, translational-energy release, and molecular-orbital calculations

Journal of the American Chemical Society ◽

10.1021/ja00210a004 ◽

1988 ◽

Vol 110 (2) ◽

pp. 347-352 ◽

Cited By ~ 28

Author(s):

Kevin F. Donchi ◽

Bruce A. Rumpf ◽

Gary D. Willett ◽

John R. Christie ◽

Peter J. Derrick

Keyword(s):

Energy Release ◽

Molecular Orbital ◽

Molecular Hydrogen ◽

Isotope Effects ◽

Molecular Orbital Calculations ◽

Translational Energy ◽

Hydrogen Elimination

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

Zeitschrift für Naturforschung A ◽

10.1515/zna-2001-0312 ◽

2001 ◽

Vol 56 (3-4) ◽

pp. 297-306 ◽

Cited By ~ 2

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.

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