This MECHEM log was prepared by Andrew Zeigarnik
(andrew@azeigarnik.msk.ru) to illustrate the paper
Metal-Catalyzed Ethylene Hydrogenation: The Method of Interactive
Search for Multiple Working Hypotheses
by authors A.V. Zeigarnik, R.E. Valdes-Perez, and O.N. Temkin.
MECHEM is an interactive discovery program that helps ensure that no
simple multistep reaction pathways are overlooked. MECHEM is widely
applicable, it builds on the user's current knowledge of a reaction,
and it provides a convenient interface for articulating that knowledge
flexibly to the program.
This interface is organized as a hierarchical collection of contexts.
For example, if you want to specify the starting materials, you should
enter the Starting Materials context as shown below. To talk about
mechanisms that MECHEM finds, enter the Mechanisms context when it
appears. The same holds for Steps, Conjectured Species, and so on.
Type the commands shown within brackets [] to enter or quit contexts.
Starting Materials [sm]
Parameters and Switches [ps]
Species catalogue [sc]
About MECHEM [ab]
Quit [q]
? sm
Add one starting material or a parenthesized list [a]
List the starting materials [l]
Delete a starting material [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sc]
Quit dealing with starting materials [q]
? a
starting material (or a parenthesized list): (ethylene H2 M MM)
Add one starting material or a parenthesized list [a]
List the starting materials [l]
Delete a starting material [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sc]
Quit dealing with starting materials [q]
? l
(CH2=CH2 M MM H2)
Add one starting material or a parenthesized list [a]
List the starting materials [l]
Delete a starting material [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sc]
Quit dealing with starting materials [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to ()
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? p
Note: no distinction is made in this context between products and
intermediates
Add one product or a parenthesized list [a]
List the products [l]
Delete a product [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sh]
Quit dealing with products [q]
? a
product (or a parenthesized list): (CH3-CH3)
Add one product or a parenthesized list [a]
List the products [l]
Delete a product [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sh]
Quit dealing with products [q]
? l
(CH3-CH3)
Add one product or a parenthesized list [a]
List the products [l]
Delete a product [d]
Load from a file [f]
Show the catalogued species that MECHEM recognizes [sh]
Quit dealing with products [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Steps [st]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? c
Add a constraint [a]
List the current constraints [l]
Quit dealing with constraints [q]
? a
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? f
Maximum coefficient in conjectured formulas [x]
Maximum coefficient in conjectured formulas (allow exceptions) [xx]
Minimum coefficient in conjectured formulas [n]
Minimum coefficient in conjectured formulas (allow exceptions) [nx]
Maximum coefficient sum in conjectured formulas [xs]
Maximum overall number of atoms [ma]
Maximum overall number of polyvalent atoms [mp]
Reject conjectured formula [r]
Reject conjectured formula pattern [rp]
Specify list of possible conjectured formulas [sl]
Quit adding constraints on formulas [q]
? r
Enter formula in parentheses (C H M): (0 1 0)
Maximum coefficient in conjectured formulas [x]
Maximum coefficient in conjectured formulas (allow exceptions) [xx]
Minimum coefficient in conjectured formulas [n]
Minimum coefficient in conjectured formulas (allow exceptions) [nx]
Maximum coefficient sum in conjectured formulas [xs]
Maximum overall number of atoms [ma]
Maximum overall number of polyvalent atoms [mp]
Reject conjectured formula [r]
Reject conjectured formula pattern [rp]
Specify list of possible conjectured formulas [sl]
Quit adding constraints on formulas [q]
? x
Element from (C H M): c
Maximum coefficient: 2
Maximum coefficient in conjectured formulas [x]
Maximum coefficient in conjectured formulas (allow exceptions) [xx]
Minimum coefficient in conjectured formulas [n]
Minimum coefficient in conjectured formulas (allow exceptions) [nx]
Maximum coefficient sum in conjectured formulas [xs]
Maximum overall number of atoms [ma]
Maximum overall number of polyvalent atoms [mp]
Reject conjectured formula [r]
Reject conjectured formula pattern [rp]
Specify list of possible conjectured formulas [sl]
Quit adding constraints on formulas [q]
? x
Element from (C H M): m
Maximum coefficient: 3
Maximum coefficient in conjectured formulas [x]
Maximum coefficient in conjectured formulas (allow exceptions) [xx]
Minimum coefficient in conjectured formulas [n]
Minimum coefficient in conjectured formulas (allow exceptions) [nx]
Maximum coefficient sum in conjectured formulas [xs]
Maximum overall number of atoms [ma]
Maximum overall number of polyvalent atoms [mp]
Reject conjectured formula [r]
Reject conjectured formula pattern [rp]
Specify list of possible conjectured formulas [sl]
Quit adding constraints on formulas [q]
? q
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? str
Reject species [r]
Reject three-element bridge within structures [rb]
Reject non-closed elemental path [rp]
Reject n-member elemental cycle [rn]
Reject structural fragment [rf]
Require an element at full valence [fv]
Require an element at a specified valence or greater [sv]
No more than N atoms or sites may be at incomplete valence [iv]
Reject gas-phase free radicals [gf]
Reject gas-phase free radicals (with exceptions) [gfx]
Polyvalent element cannot form multiple topological links [mt]
Constrain identities of adjacent atoms [ci]
Reject all cyclic structures [rc]
Reject cyclic structures of specified length [rcl]
Specify list of possible conjectured species [sl]
Quit adding constraints on structures [q]
? fv
List of elements to be always at full valence
from (H C ALL) or enter `all': (all)
Reject species [r]
Reject three-element bridge within structures [rb]
Reject non-closed elemental path [rp]
Reject n-member elemental cycle [rn]
Reject structural fragment [rf]
Require an element at full valence [fv]
Require an element at a specified valence or greater [sv]
No more than N atoms or sites may be at incomplete valence [iv]
Reject gas-phase free radicals [gf]
Reject gas-phase free radicals (with exceptions) [gfx]
Polyvalent element cannot form multiple topological links [mt]
Constrain identities of adjacent atoms [ci]
Reject all cyclic structures [rc]
Reject cyclic structures of specified length [rcl]
Specify list of possible conjectured species [sl]
Quit adding constraints on structures [q]
? q
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? r
Reject pair of reactants [rp]
Reject unimolecular reactant [ru]
Reject bimolecular reactant [rb]
Reject all unimolecular steps [au]
Reject all bimolecular steps [ab]
Elements must be present in every step [e]
Species cannot appear on the left-hand side of a step [lhs]
No reactions between any gaseous and surface species (Eley/Rideal) [er]
No reactions between gaseous species (allow exceptions) and surface species
[erx]
No reactions between specific species and any surface species) [sa]
No reactions between any two surface species (Langmuir/Hinshelwood) [lh]
No reactions between any two surface species that contain an element [ae]
Every co-reactant with specific species must contain an element [se]
Specify possible co-reactants with a specific species [sp]
Maximum overall elemental composition of reactants [x]
Minimum overall elemental composition of reactants [n]
Specify list of possible reactant pairs [sl]
Quit adding constraints on reactants [q]
? e
Enter an element or list of elements
(every step will be required to involve at least one of these): M
Reject pair of reactants [rp]
Reject unimolecular reactant [ru]
Reject bimolecular reactant [rb]
Reject all unimolecular steps [au]
Reject all bimolecular steps [ab]
Elements must be present in every step [e]
Species cannot appear on the left-hand side of a step [lhs]
No reactions between any gaseous and surface species (Eley/Rideal) [er]
No reactions between gaseous species (allow exceptions) and surface species
[erx]
No reactions between specific species and any surface species) [sa]
No reactions between any two surface species (Langmuir/Hinshelwood) [lh]
No reactions between any two surface species that contain an element [ae]
Every co-reactant with specific species must contain an element [se]
Specify possible co-reactants with a specific species [sp]
Maximum overall elemental composition of reactants [x]
Minimum overall elemental composition of reactants [n]
Specify list of possible reactant pairs [sl]
Quit adding constraints on reactants [q]
? x
Element from (C H M): C
Maximum coefficient: 2
Reject pair of reactants [rp]
Reject unimolecular reactant [ru]
Reject bimolecular reactant [rb]
Reject all unimolecular steps [au]
Reject all bimolecular steps [ab]
Elements must be present in every step [e]
Species cannot appear on the left-hand side of a step [lhs]
No reactions between any gaseous and surface species (Eley/Rideal) [er]
No reactions between gaseous species (allow exceptions) and surface species
[erx]
No reactions between specific species and any surface species) [sa]
No reactions between any two surface species (Langmuir/Hinshelwood) [lh]
No reactions between any two surface species that contain an element [ae]
Every co-reactant with specific species must contain an element [se]
Specify possible co-reactants with a specific species [sp]
Maximum overall elemental composition of reactants [x]
Minimum overall elemental composition of reactants [n]
Specify list of possible reactant pairs [sl]
Quit adding constraints on reactants [q]
? q
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? q
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? l
1. Reject formula H
2. Every conjectured species has at most two C atoms
3. Every conjectured species has at most three M sites
4. All elements must be at full valence
5. The site M must be present in all steps
6. Reactants involve jointly at most two C atoms
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Steps [st]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? ps
List the current parameter settings [l]
Change the current parameter settings [ch]
Restore the default parameter settings [re]
Quit dealing with parameters [q]
? ch
1. Start with 0 conjectured species
2. Consider at most 7 conjectured species
3. At most 3 changes to the topology of molecules per step
4. Exchange reactions (AB + CD --> AC + BD) are OK
5. Don't reject all except exchange reactions (AB + CD --> AC + BD)
6. A starting material can be produced from the other starting materials
7. Isomers are allowed
8. Reject isomerization steps (A --> A')
9. Allowed valences are: C(4) H(1) M(1)
Select a parameter to change: 8
Reject isomerization steps (A --> A')
Flip the setting? y
List the current parameter settings [l]
Change the current parameter settings [ch]
Restore the default parameter settings [re]
Quit dealing with parameters [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Steps [st]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? r
Conjecturing 0 species
With 1 step
Conjecturing 1 species
With 1 step
Conjecturing 2 species
With 2 steps
With 3 steps
Found three mechanisms!
(after about zero seconds)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? m
List the first N of 3 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 3 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? 3
Mechanisms presented in Scheme 1 of the manuscript
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + *HM* --> *CH3-CH2M*
3. *HM* + *CH3-CH2M* --> MM + CH3-CH3
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + *HM* --> *CH3-CH2M*
3. H2 + *CH3-CH2M* --> CH3-CH3 + *HM*
1. CH2=CH2 + MM --> *CH2M-CH2M*
2. H2 + *CH2M-CH2M* --> 2(*CH3M*)
3. 2(*CH3M*) --> MM + CH3-CH3
List the first N of 3 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 3 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? q
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? st
Histogram of the steps from all current mechanisms [h]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? h
Frequency Reactants --[topological distance]--> Products
1. 2 MM + H2 --[3]--> 2(*HM*)
2. 2 CH2=CH2 + *HM* --[3]--> *CH3-CH2M*
3. 1 *HM* + *CH3-CH2M* --[3]--> MM + CH3-CH3
4. 1 H2 + *CH3-CH2M* --[4]--> CH3-CH3 + *HM*
5. 1 CH2=CH2 + MM --[2]--> *CH2M-CH2M*
6. 1 H2 + *CH2M-CH2M* --[4]--> 2(*CH3M*)
7. 1 2(*CH3M*) --[3]--> MM + CH3-CH3
Histogram of the steps from all current mechanisms [h]
Reject a list of steps [rl]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? rl
Enter number of step to be rejected (list is OK): (2 6)
Histogram of the steps from all current mechanisms [h]
Reject a list of steps [rl]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? q
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Apply the new constraints
to the existing mechanisms [ap]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? c
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? l
1. Reject formula H
2. Every conjectured species has at most two C atoms
3. Every conjectured species has at most three M sites
4. All elements must be at full valence
5. The site M must be present in all steps
6. Reactants involve jointly at most two C atoms
7. Reject the step: (CH2=CH2 *HM*) --> (*CH3-CH2M*)
8. Reject the step: (H2 *CH2M-CH2M*) --> (*CH3M* *CH3M*)
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Apply the new constraints
to the existing mechanisms [ap]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? r
Conjecturing 0 species
With 1 step
Conjecturing 1 species
With 1 step
Conjecturing 2 species
With 2 steps
Conjecturing 3 species
With 2 steps ... searched 1/4, 1/2, 3/4, done.
With 3 steps
Found four mechanisms!
(after about two seconds)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? m
List the first N of 4 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 3 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? 4
Mechanisms presented in Scheme 2 of the manuscript
1. CH2=CH2 + MM --> *CH2M-CH2M*
2. H2 + *CH2M-CH2M* --> *HM* + *CH3-CH2M*
3. *HM* + *CH3-CH2M* --> MM + CH3-CH3
1. CH2=CH2 + MM --> *CH2M-CH2M*
2. H2 + *CH2M-CH2M* --> *HM* + *CH3-CH2M*
3. H2 + *CH3-CH2M* --> CH3-CH3 + *HM*
1. CH2=CH2 + MM --> *HM* + *CH2=CHM*
2. H2 + *CH2=CHM* --> *CH3-CH2M*
3. *HM* + *CH3-CH2M* --> MM + CH3-CH3
1. CH2=CH2 + MM --> *HM* + *CH2=CHM*
2. H2 + *CH2=CHM* --> *CH3-CH2M*
3. H2 + *CH3-CH2M* --> CH3-CH3 + *HM*
List the first N of 4 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 3 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? q
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? st
Histogram of the steps from all current mechanisms [h]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? h
Frequency Reactants --[topological distance]--> Products
1. 2 CH2=CH2 + MM --[2]--> *CH2M-CH2M*
2. 2 H2 + *CH2M-CH2M* --[4]--> *HM* + *CH3-CH2M*
3. 2 *HM* + *CH3-CH2M* --[3]--> MM + CH3-CH3
4. 2 H2 + *CH3-CH2M* --[4]--> CH3-CH3 + *HM*
5. 2 CH2=CH2 + MM --[3]--> *HM* + *CH2=CHM*
6. 2 H2 + *CH2=CHM* --[3]--> *CH3-CH2M*
Histogram of the steps from all current mechanisms [h]
Reject a list of steps [rl]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? rl
Enter number of step to be rejected (list is OK): (5 2)
Histogram of the steps from all current mechanisms [h]
Reject a list of steps [rl]
Select a step from the histogram [s]
Show the steps involving a user-input species [shu]
List the feasible steps among the user-input species [lu]
Select a step from the feasible steps among the user-input species [su]
Quit dealing with steps [q]
? q
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Apply the new constraints
to the existing mechanisms [ap]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? c
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? l
1. Reject formula H
2. Every conjectured species has at most two C atoms
3. Every conjectured species has at most three M sites
4. All elements must be at full valence
5. The site M must be present in all steps
6. Reactants involve jointly at most two C atoms
7. Reject the step: (CH2=CH2 *HM*) --> (*CH3-CH2M*)
8. Reject the step: (H2 *CH2M-CH2M*) --> (*CH3M* *CH3M*)
9. Reject the step: (CH2=CH2 MM) --> (*HM* *CH2=CHM*)
10. Reject the step: (H2 *CH2M-CH2M*) --> (*HM* *CH3-CH2M*)
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Apply the new constraints
to the existing mechanisms [ap]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? r
Conjecturing 0 species
With 1 step
Conjecturing 1 species
With 1 step
Conjecturing 2 species
With 2 steps
Conjecturing 3 species
With 2 steps ... searched 1/4, 1/2, 3/4, done.
With 3 steps
With 4 steps
Found four mechanisms!
(after about one second)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? m
List the first N of 4 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 4 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? 4
Mechanisms presented in Scheme 3 of the manuscript
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + *HM* --> H2 + *CH2=CHM*
3. H2 + *CH2=CHM* --> *CH3-CH2M*
4. *HM* + *CH3-CH2M* --> MM + CH3-CH3
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + *HM* --> H2 + *CH2=CHM*
3. H2 + *CH2=CHM* --> *CH3-CH2M*
4. H2 + *CH3-CH2M* --> CH3-CH3 + *HM*
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + MM --> *CH2M-CH2M*
3. *HM* + *CH2M-CH2M* --> MM + *CH3-CH2M*
4. *HM* + *CH3-CH2M* --> MM + CH3-CH3
1. MM + H2 --> 2(*HM*)
2. CH2=CH2 + MM --> *CH2M-CH2M*
3. *HM* + *CH2M-CH2M* --> MM + *CH3-CH2M*
4. H2 + *CH3-CH2M* --> CH3-CH3 + *HM*
List the first N of 4 mechanisms [<N>]
Partition the mechanisms into similar classes [par]
Select a mechanism [s]
Reject future mechanisms whose first 4 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? q
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? c
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? a
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? r
Reject pair of reactants [rp]
Reject unimolecular reactant [ru]
Reject bimolecular reactant [rb]
Reject all unimolecular steps [au]
Reject all bimolecular steps [ab]
Elements must be present in every step [e]
Species cannot appear on the left-hand side of a step [lhs]
No reactions between any gaseous and surface species (Eley/Rideal) [er]
No reactions between gaseous species (allow exceptions) and surface species
[erx]
No reactions between specific species and any surface species) [sa]
No reactions between any two surface species (Langmuir/Hinshelwood) [lh]
No reactions between any two surface species that contain an element [ae]
Every co-reactant with specific species must contain an element [se]
Specify possible co-reactants with a specific species [sp]
Maximum overall elemental composition of reactants [x]
Minimum overall elemental composition of reactants [n]
Specify list of possible reactant pairs [sl]
Quit adding constraints on reactants [q]
? er
Done.
Reject pair of reactants [rp]
Reject unimolecular reactant [ru]
Reject bimolecular reactant [rb]
Reject all unimolecular steps [au]
Reject all bimolecular steps [ab]
Elements must be present in every step [e]
Species cannot appear on the left-hand side of a step [lhs]
No reactions between any gaseous and surface species (Eley/Rideal) [er]
No reactions between gaseous species (allow exceptions) and surface species
[erx]
No reactions between specific species and any surface species) [sa]
No reactions between any two surface species (Langmuir/Hinshelwood) [lh]
No reactions between any two surface species that contain an element [ae]
Every co-reactant with specific species must contain an element [se]
Specify possible co-reactants with a specific species [sp]
Maximum overall elemental composition of reactants [x]
Minimum overall elemental composition of reactants [n]
Specify list of possible reactant pairs [sl]
Quit adding constraints on reactants [q]
? q
Atoms [a]
Formulas [f]
Topology [to]
Structures [str]
Reactants [r]
Products [p]
Steps [st]
Sequences of Steps [ss]
Full Pathways [fp]
Quit adding constraints [q]
? q
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? d
1. Reject formula H
2. Every conjectured species has at most two C atoms
3. Every conjectured species has at most three M sites
4. All elements must be at full valence
5. The site M must be present in all steps
6. Reactants involve jointly at most two C atoms
7. Reject the step: (CH2=CH2 *HM*) --> (*CH3-CH2M*)
8. Reject the step: (H2 *CH2M-CH2M*) --> (*CH3M* *CH3M*)
9. Reject the step: (CH2=CH2 MM) --> (*HM* *CH2=CHM*)
10. Reject the step: (H2 *CH2M-CH2M*) --> (*HM* *CH3-CH2M*)
11. Reject co-reactants: gas-phase + any surface species
Enter number (parenthesized list is OK) or any reply from (NONE): (7 8 9 10)
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? l
1. Reject formula H
2. Every conjectured species has at most two C atoms
3. Every conjectured species has at most three M sites
4. All elements must be at full valence
5. The site M must be present in all steps
6. Reactants involve jointly at most two C atoms
7. Reject co-reactants: gas-phase + any surface species
Add a constraint [a]
List the current constraints [l]
Delete a constraint [d]
Delete all constraints [all]
Quit dealing with constraints [q]
? q
Working on (CH2=CH2 + M + MM + H2) go to (CH3-CH3)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Apply the new constraints
to the existing mechanisms [ap]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? r
Conjecturing 0 species
With 1 step
Conjecturing 1 species
With 1 step
Conjecturing 2 species
With 2 steps
Conjecturing 3 species
With 2 steps ... searched 1/4, 1/2, 3/4, done.
With 3 steps
With 4 steps
Found one mechanism!
(after about one second)
Starting Materials [sm]
Products and Intermediates [p]
Constraints [c]
Parameters and Switches [ps]
Run MECHEM [r]
Run MECHEM and Examine Dynamic State [re]
Mechanisms [m]
Steps [st]
Conjectured species [cs]
Species catalogue [sc]
Advice [ad]
About MECHEM [ab]
Quit [q]
? m
List the mechanism [l]
Select the mechanism [s]
Reject future mechanisms whose first 4 steps match any current mechanism [r]
Reject future mechanisms that contain no new conjectured species [r2]
Reject future mechanisms in this simplicity class [r3]
Time taken to find these mechanisms [ti]
Quit dealing with mechanisms [q]
? l
Upon reformulating the problem to prohibit Eley-Rideal mechanisms, the program reported the Horiuti-Polanyi mechanism as the unique simplest:
1. MM + H2 --> 2(*HM*) 2. CH2=CH2 + MM --> *CH2M-CH2M* 3. *HM* + *CH2M-CH2M* --> MM + *CH3-CH2M* 4. *HM* + *CH3-CH2M* --> MM + CH3-CH3 List the mechanism [l] Select the mechanism [s] Reject future mechanisms whose first 4 steps match any current mechanism [r] Reject future mechanisms that contain no new conjectured species [r2] Reject future mechanisms in this simplicity class [r3] Time taken to find these mechanisms [ti] Quit dealing with mechanisms [q] ? q Starting Materials [sm] Products and Intermediates [p] Constraints [c] Parameters and Switches [ps] Run MECHEM [r] Run MECHEM and Examine Dynamic State [re] Mechanisms [m] Steps [st] Conjectured species [cs] Species catalogue [sc] Advice [ad] About MECHEM [ab] Quit [q] ? q Really exit MECHEM? y :Your total run time is 4.96 seconds :Your total connect time is 9.590659 hours :Good bye ... :Dribble file Logs/1607hrs-Sun-05-Oct-97.log closed