Fused hard sphere chains: Difference between revisions

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In the '''fused hard sphere chain''' model the ''molecule'' is built up form a string of overlapping [[hard sphere model|hard sphere sites]], each of diameter <math>\sigma</math>.
In the '''fused hard sphere chain''' model the ''molecule'' is built up form a string of overlapping [[hard sphere model|hard sphere sites]], each of diameter <math>\sigma</math>.


An effective number of monomers can be applied to the fused hard sphere chain model by using the relarion (Ref. 4 Eq. 2.18)
An effective number of monomers can be applied to the fused hard sphere chain model by using the relarion (Ref. <ref>[http://dx.doi.org/10.1063/1.470528    Yaoqi Zhou, Carol K. Hall and George Stell "Thermodynamic perturbation theory for fused hard-sphere and hard-disk chain fluids", Journal of Chemical Physics '''103''' pp. 2688-2695 (1995)]</ref> Eq. 2.18)


<math>m_{\rm effective} = \frac{[1+(m-1)L^*]^3}{[1+(m-1)L^*(3-L^{*2})/2]^2}</math>
:<math>m_{\rm effective} = \frac{[1+(m-1)L^*]^3}{[1+(m-1)L^*(3-L^{*2})/2]^2}</math>


where ''m'' is the number of monomer units in the model, and <math>L^*=L/\sigma</math> is the reduced bond length.  
where <math>m</math> is the number of monomer units in the model, and <math>L^*=L/\sigma</math> is the reduced bond length.  


The volume of the fused hard sphere chain is given by (Ref. 5 Eq. 13)
The volume of the fused hard sphere chain is given by (Ref. <ref name="BVD">[http://dx.doi.org/10.1063/1.459523 T. Boublík, C. Vega, and M. Diaz-Peña "Equation of state of chain molecules", Journal of Chemical Physics '''93''' pp. pp. 730-736 (1990)]</ref> Eq. 13)


:<math>V_{\rm FHSC} =\frac{1}{6} \pi \sigma^3 \left( 1 + \frac{m-1}{2}L^* \left(3-L^{*2}\right) \right)</math>
:<math>V_{\rm FHSC} =\frac{\pi \sigma^3}{6}  \left( 1 + (m-1)\frac{3L^*  - L^{*3}}{2} \right)  ~~~~
\scriptstyle{
L^* \leq 1 ~\and~ \left(\gamma=\pi ~ \or ~
L^* \sin{\frac\gamma{2}} \geq \frac{1}{2}\right)
}
</math>


and the surface area is given by (Ref. 5 Eq. 12)
where <math>0<\gamma \leq \pi</math> is the minimal bond angle, and the surface area is given by (Ref.<ref name="BVD" />  Eq. 12)
 
:<math>S_{\mathrm FHSC} = \pi \sigma^2 \left( 1+\left( m-1 \right) L^* \right)</math>
==Equation of state==
The Vörtler and Nezbeda [[Equations of state | equation of state]] is given by <ref>[https://doi.org/10.1002/bbpc.19900940505 Horst L. Vörtler and I. Nezbeda "Volume-explicit equation of state and excess volume of mixing of fused hard sphere fluids", Berichte der Bunsen-Gesellschaft '''94''' pp. 559-563 (1990)]</ref>
 
:<math>Z_{\mathrm{FHSC}}= 1+ (1+3\alpha)\eta_0(P^*) + C_{\rm FHSC}[\eta_0(P^*)]^{1.83}</math>
 
where
 
:<math>C_{\rm FHSC} = 5.66\alpha(1-0.045[\alpha-1]^{1/2}\eta_0)</math>
 
and
 
:<math>\eta_0(P^*) = \frac{\sqrt{1+4(1+3\alpha)P^*}-1}{2+6\alpha}</math>
 
The Waziri and Hamad [[Equations of state | equation of state]] for fused hard sphere chain fluids is given by <ref>[http://dx.doi.org/10.1021/ie800755s Saidu M. Waziri and Esam Z. Hamad "Volume-Explicit Equation of State for Fused Hard Sphere Chain Fluids", Industrial & Engineering Chemistry Research '''47''' pp. 9658-9662 (2008)]</ref>
 
:<math>Z_{\mathrm{FHSC}} = 1 + 4m_{\mathrm{eff}}P^{*} + \frac{3}{4}m_{\mathrm{eff}}P^{*}\ln\left[\frac{3+P^{*}}{3+25P^{*}}\right] + \frac{216(m_{\mathrm{eff}} - 1)P^{*}}{(3+P^{*})(3+25P^{*})\{16+3\ln[(3+P^{*})/(3+25P^{*})]\}}</math>
 
where
 
:<math>m_{\mathrm{eff}}=\frac{2+3(m-1)L^{*}+2(m-1)^{2}L^{*2}+(m-1)L^{*3}}{2+3(m-1)L^{*}-(m-1)L^{*3}}</math>


:<math>S_{\rm FHSC} = \pi \sigma^2 \left( 1+\left( m-1 \right) L^* \right)</math>
==See also==
==See also==
*[[Rigid fully flexible fused hard sphere model]]
*[[Rigid fully flexible fused hard sphere model]]
==References==
==References==
#[http://dx.doi.org/10.1080/00268979100100191 M. Whittle and A. J. Masters "Liquid crystal formation in a system of fused hard spheres", Molecular Physics '''72''' pp. 247-265 (1991)]
<references/>
#[http://dx.doi.org/10.1103/PhysRevE.64.011703  Carl McBride, Carlos Vega, and Luis G. MacDowell "Isotropic-nematic phase transition: Influence of intramolecular flexibility using a fused hard sphere model" Physical Review E '''64''' 011703 (2001)]
;Related reading
#[http://dx.doi.org/10.1063/1.1517604      Carl McBride and Carlos Vega "A Monte Carlo study of the influence of molecular flexibility on the phase diagram of a fused hard sphere model", Journal of Chemical Physics '''117''' pp. 10370-10379  (2002)]
*[http://dx.doi.org/10.1080/00268979100100191 M. Whittle and A. J. Masters "Liquid crystal formation in a system of fused hard spheres", Molecular Physics '''72''' pp. 247-265 (1991)]
#[http://dx.doi.org/10.1063/1.470528    Yaoqi Zhou, Carol K. Hall and George Stell "Thermodynamic perturbation theory for fused hard-sphere and hard-disk chain fluids", Journal of Chemical Physics '''103''' pp. 2688-2695 (1995)]
*[http://dx.doi.org/10.1103/PhysRevE.64.011703  Carl McBride, Carlos Vega, and Luis G. MacDowell "Isotropic-nematic phase transition: Influence of intramolecular flexibility using a fused hard sphere model" Physical Review E '''64''' 011703 (2001)]
#[http://dx.doi.org/10.1063/1.459523    T. Boublík, C. Vega, and M. Diaz-Peña "Equation of state of chain molecules", Journal of Chemical Physics '''93''' pp. pp. 730-736 (1990)]
*[http://dx.doi.org/10.1063/1.1517604      Carl McBride and Carlos Vega "A Monte Carlo study of the influence of molecular flexibility on the phase diagram of a fused hard sphere model", Journal of Chemical Physics '''117''' pp. 10370-10379  (2002)]
*[http://dx.doi.org/10.1080/002689798168989 Antoine Chamoux and Aurelien Perera "On the linear hard sphere chain fluids", Molecular Physics '''93'' pp. 649-661 (1998)]
[[category:liquid crystals]]
[[category:liquid crystals]]
[[category:models]]
[[category:models]]

Latest revision as of 19:45, 23 December 2018

Example of the fused hard sphere chain model, shown here in a linear configuration.

In the fused hard sphere chain model the molecule is built up form a string of overlapping hard sphere sites, each of diameter .

An effective number of monomers can be applied to the fused hard sphere chain model by using the relarion (Ref. [1] Eq. 2.18)

where is the number of monomer units in the model, and is the reduced bond length.

The volume of the fused hard sphere chain is given by (Ref. [2] Eq. 13)

where is the minimal bond angle, and the surface area is given by (Ref.[2] Eq. 12)

Equation of state[edit]

The Vörtler and Nezbeda equation of state is given by [3]

where

and

The Waziri and Hamad equation of state for fused hard sphere chain fluids is given by [4]

where

See also[edit]

References[edit]

Related reading