Free energy difference of pitch variation and calculation of the order–disorder transition in block copolymer systems using thermodynamic integration

2015 ◽  
Vol 2 (7) ◽  
pp. 075301 ◽  
Author(s):  
Andrew J Peters ◽  
Richard A Lawson ◽  
Benjamin D Nation ◽  
Peter J Ludovice ◽  
Clifford L Henderson
Keyword(s):  
Free Energy ◽  
Block Copolymer ◽  
Energy Difference ◽  
Thermodynamic Integration ◽  
Free Energy Difference ◽  
Disorder Transition

On the relationship between free energy difference calculations by thermodynamic integration and harmonic frequency analysis

2009 ◽  
Vol 87 (3) ◽  
pp. 496-501
Author(s):  
Jason Jechow ◽  
Tom Ziegler
Keyword(s):  
Free Energy ◽  
Statistical Mechanics ◽  
Frequency Analysis ◽  
Helmholtz Free Energy ◽  
Energy Difference ◽  
Thermodynamic Integration ◽  
Point Of View ◽  
Harmonic Frequency ◽  
Free Energy Difference ◽  
The Relationship

Harmonic frequency analysis (HFA), based on statistical mechanics, is a widely used and powerful tool for evaluating free energy changes between molecular states. It has, as such, been employed extensively to evaluate the free energy of reaction and activation for chemical processes. Alternatively, free energy differences can be calculated using thermodynamic integration (TI). In TI, the force on a constrained reaction coordinate is calculated, and this force from a to b is integrated to obtain the Helmholtz free energy change ΔAab. Although HFA and TI clearly are related from a fundamental statistical mechanics point-of-view, the relationship is not immediately obvious when one considers the quite different procedures applied in the two methods. This article provides a detailed analysis and proof of the relation between HFA and TI.

Conformational analysis of 1,4-disubstituted cyclohexanes. III. trans-1,4-Di(trifluoroacetoxy)cyclohexane

1969 ◽  
Vol 47 (3) ◽  
pp. 429-431 ◽  
Author(s):  
Gordon Wood ◽  
E. P. Woo ◽  
M. H. Miskow
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Free Energy ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Conformational Analysis ◽  
Integration Method ◽  
Standard Free Energy ◽  
Energy Difference ◽  
Free Energy Difference ◽  
Conformational Free Energy

By the low temperature nuclear magnetic resonance integration method the standard free energy difference between the diequatorial and the diaxial forms of 1-H,4-H-trans-1,4-di(trifluoroacetoxy)-cyclohexane-d8 was found to be 77 ± 5 cal/mole. The conformational free energy (−ΔG0) of the trifluoroacetoxy group in the monosubstituted cyclohexane was 485 ± 4 cal/mole at the same temperature. The non-additivity of the −ΔG0 values is discussed in terms of transannular electrostatic interaction.

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