Example selectivity

Introduction

In this example, we show how to calculate selectivities and how to perform a degree of selectivity control analysis. We perform a calculation on a relatively simple chemokinetic network wherein a product A can be converted to product E or F. We wish to analyze which elementary reaction steps control the selectivity to E or F.

Input

In this example, the following input file is used:

&compounds
A;		0;	1
E;		0;	0
F;		0;	0
A*;		1;	0 ; 1
B*;		1;	0 ; 1
C*;		1;	0 ; 1
D*;		1;	0 ; 1
E*;		1;	0 ; 1
F*;		1;	0 ; 1
*;		1;	1.0
&reactions
#						m^2		amu			K	sigma	sticking	J/mol
HK; {A} + {*} => {A*};	1e-20;	  1;	   1;	 1;		1;			 80e3 ; 1
HK; {E} + {*} => {E*};	1e-20;	  1;	   1;	 1;		1;			 80e3 ; 1
HK; {F} + {*} => {F*};	1e-20;	  1;	   1;	 1;		1;			 80e3 ; 1
#									vf		vb		Eaf		Eab
AR; {A*}	     => {B*};			1e13;	1e13;	 90e3;	 90e3 ;1
AR; {B*}	     => {C*};			1e13;	1e13;	 80e3;	 90e3 ;1
AR; {B*}             => {D*};	1e13;	1e13;	 70e3;	 80e3 ;1
AR; {C*}	     => {E*};			1e13;	1e13;	 70e3;	120e3 ;1
AR; {D*}	     => {F*};			1e13;	1e13;	 70e3;	 90e3 ;1
&settings
TYPE = SEQUENCERUN
PRESSURE = 1
REAGENTS = {A}
KEYCOMPONENT = {F}
EACT=1
ORDERS=1
DRC=1
TDRC=0
DEBUG=1
USETIMESTAMP=0
&runs
300;	1e6;	1e-10;	1e-10
350;	1e6;	1e-10;	1e-10
400;	1e6;	1e-10;	1e-10
450;	1e5;	1e-10;	1e-10
500;	1e4;	1e-10;	1e-10
550;	1e3;	1e-10;	1e-10
600;	1e2;	1e-10;	1e-10
650;	1e1;	1e-10;	1e-10
700;	1e1;	1e-10;	1e-10
750;	1e1;	1e-10;	1e-10
800;	1e0;	1e-10;	1e-10
850;	1e0;	1e-10;	1e-10
900;	1e0;	1e-10;	1e-10
950;	1e0;	1e-10;	1e-10
1000;	1e0;	1e-10;	1e-10
1100;	1e0;	1e-10;	1e-10
1200;	1e0;	1e-10;	1e-10
1300;	1e0;	1e-10;	1e-10
1400;	1e0;	1e-10;	1e-10
1500;	1e0;	1e-10;	1e-10
1600;	1e0;	1e-10;	1e-10
1700;	1e0;	1e-10;	1e-10
1800;	1e0;	1e-10;	1e-10
1900;	1e0;	1e-10;	1e-10
2000;	1e0;	1e-10;	1e-10

Running the calculation

The first step is to perform a regular calculation.

./mkmcxx -i input.mkm

Turn-over-frequencies as a function of temperature.

This results in the creation of a run folder wherein all the raw data is written. A plot of the turn-over frequencies is given on the right. We can easily see that there is a distinct selectivity pattern for E over F.