Vapor pressure isotope effects in methyl fluoride studied by density functional theory

2007 ◽  
Vol 440 (1-3) ◽  
pp. 19-23 ◽  
Author(s):  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Density Functional Theory ◽  
Vapor Pressure ◽  
Density Functional ◽  
Isotope Effects ◽  
Functional Theory ◽  
Methyl Fluoride

Hydrogen and Carbon Vapour Pressure Isotope Effects in Liquid Fluoroform Studied by Density Functional Theory

2017 ◽  
Vol 72 (3) ◽  
pp. 193-200 ◽  
Author(s):  
Takao Oi ◽  
Ryota Mitome ◽  
Satoshi Yanase
Keyword(s):  
Density Functional Theory ◽  
Intermolecular Interactions ◽  
Vapour Pressure ◽  
Density Functional ◽  
Isotope Effects ◽  
Experimental Results ◽  
Temperature Dependent ◽  
Functional Theory ◽  
Temperature Dependences

AbstractH/D and 12C/13C vapour pressure isotope effects (VPIEs) in liquid fluoroform (CHF3) were studied at the MPW1PW91/6-31 ++ G(d) level of theory. The CHF3 monomer and CHF3 molecules surrounded by other CHF3 molecules in every direction in CHF3 clusters were used as model molecules of vapour and liquid CHF3. Although experimental results in which the vapour pressure of liquid 12CHF3 is higher than that of liquid 12CDF3 and the vapour pressure of liquid 13CHF3 is higher than that of liquid 12CHF3 between 125 and 212 K were qualitatively reproduced, the present calculations overestimated the H/D VPIE and underestimated the 12C/13C VPIE. Temperature-dependent intermolecular interactions between hydrogen and fluorine atoms of neighbouring molecules were required to explain the temperature dependences of both H/D and 12C/13C VPIEs.

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