ChemWiki - User contributions [en]

MRD:dlk188

2020-05-22T23:51:52Z

2020-05-22T22:30:05Z

Dlk18:

2020-05-22T21:54:06Z

Dlk18: /* Reaction Dynamics */

== Exercise 1 ==
===Transition state===

On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be approximately 0.00. As the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” below demonstrates the symmetry of the transition state; equal distances between A-B and B-C . A-C is double A-B.
[[File:dlk18_ex1_indistance_vs_time.png|300px|Internuclear distance vs Time for transition state of H-H-H system]]
=== MEP ===
Comment on how the ''mep'' and the trajectory you just calculated differ.

mep always resets to 0, no oscillation, shorter bc gradient =0 therefore stops once it reaches the bottom of the energy well.

Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the transition state barrier; i.e initially could be seen as reactive as the reactants do react to form products, but then the reverse reaction occurs and the trajectory is taken back to reactants. This is also shown clearly in the animation and contour plot.
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values and hence an overestimate.

== Exercise 2 ==

=== PES Inspection ===

The F-H-H system was set up with the H2 molecule approaching the Fluorine atom. The potential energy surface shows that the F + H2 reaction is exothermic, and the HF + H reaction is endothermic. This indicates that the HF bond is of higher strength than the HH bond.

Finding the Transition State:

The Transition state was estimated the same way as the previous system, though this time the transition state is asymmetric. Using Hammond's postulate and the fact that the reaction is exothermic, the (early) transition state was estimated to be X. This is confirmed by the force values X AND X and the eigenvector (omega squared values): X,X. The change in sign indicating the presence of a saddle point.

The activation energy:

The activation energy for each reaction was found in different ways.

For the HF + H reaction, an MEP calculation was performed to displace the reaction from the transition state towards the reactants. This was done using 4000 steps. The plot below demonstrates the energy displacement from the transition state and shows the energy drop into the well of pure reactant state:
The activation energy was found to be 124kj/mol approximately.

[[File:activation_dlk18.png|300px|Energy vs Time showing the displacement of transition state to reactants for HF + H]]

For the H2 + F reaction, the activation energy was found using Hammond's Postulate; kowing the reaction is exothermic, the expected activation energy would be small. This was found by displacing the distance of the HF atom 4000pm away, ensuring the energy would be that of pure reactant only in this case.
The activation energy was found to be 1 kj/mol approximately.

=== Reaction Dynamics ===

The reaction trajectory for H2 + F is plotted below:

[[File:rxn_dynamic_dlk18.png|300px|reaction trajectory for H2 + F]] [[File:mom_dlk18.png|300px|Momentum vs. time for H2 + F]]

The reaction trajectory shows oscillation even in the product region of this reaction. This is shown more clearly in the momentum vs. time plot.

Exothermic reactions like this can be classified as having attractive or repulsive potential energy surfaces. The oscillation implies that there is vibrational energy within the product.
By varying the momentum of r(HH) we are able to determine the type of energy surface. The plot below demonstrates this:

[[File:rep_dlk18.png|300px|repulsive PES for H2 + F reaction]]

By varying r(HH) momentum and looking at this plot, there is clear indication of the reaction mechanism being governed by the release in energy from the repulsion between the HH atoms. The mechanism of this reaction goes via the repulsion between the H-H atoms initially. It is the energy released due to the repulsion pushes the H atom towards the F atom and in turn produces vibrational energy in the HF product. This therefore implies a mixed energy release. The implications of this mean that there is vibrational energy in the product as well as translational energy. The key thing to note here is that the presence of vibrational energy enables this to be tested using IR spectroscopy experimentally, due to the vibrational excitation. When studying potential energy surfaces, Infrared chemiluminescence (IRCL) is a common method. This method relies on the emission of infrared photons from the excited state. Therefore, the proposed mechanism for the energy release in this reaction could be confirmed using this method.

File:Rep dlk18.png

2020-05-22T21:26:46Z

Dlk18:

MRD:dlk188

2020-05-22T21:26:07Z

Dlk18: /* Reaction Dynamics */

== Exercise 1 ==
===Transition state===

On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be approximately 0.00. As the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” below demonstrates the symmetry of the transition state; equal distances between A-B and B-C . A-C is double A-B.
[[File:dlk18_ex1_indistance_vs_time.png|300px|Internuclear distance vs Time for transition state of H-H-H system]]
=== MEP ===
Comment on how the ''mep'' and the trajectory you just calculated differ.

mep always resets to 0, no oscillation, shorter bc gradient =0 therefore stops once it reaches the bottom of the energy well.

Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the transition state barrier; i.e initially could be seen as reactive as the reactants do react to form products, but then the reverse reaction occurs and the trajectory is taken back to reactants. This is also shown clearly in the animation and contour plot.
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values and hence an overestimate.

== Exercise 2 ==

=== PES Inspection ===

The F-H-H system was set up with the H2 molecule approaching the Fluorine atom. The potential energy surface shows that the F + H2 reaction is exothermic, and the HF + H reaction is endothermic. This indicates that the HF bond is of higher strength than the HH bond.

Finding the Transition State:

The Transition state was estimated the same way as the previous system, though this time the transition state is asymmetric. Using Hammond's postulate and the fact that the reaction is exothermic, the (early) transition state was estimated to be X. This is confirmed by the force values X AND X and the eigenvector (omega squared values): X,X. The change in sign indicating the presence of a saddle point.

The activation energy:

The activation energy for each reaction was found in different ways.

For the HF + H reaction, an MEP calculation was performed to displace the reaction from the transition state towards the reactants. This was done using 4000 steps. The plot below demonstrates the energy displacement from the transition state and shows the energy drop into the well of pure reactant state:
The activation energy was found to be 124kj/mol approximately.

[[File:activation_dlk18.png|300px|Energy vs Time showing the displacement of transition state to reactants for HF + H]]

For the H2 + F reaction, the activation energy was found using Hammond's Postulate; kowing the reaction is exothermic, the expected activation energy would be small. This was found by displacing the distance of the HF atom 4000pm away, ensuring the energy would be that of pure reactant only in this case.
The activation energy was found to be 1 kj/mol approximately.

=== Reaction Dynamics ===

The reaction trajectory for H2 + F is plotted below:

[[File:rxn_dynamic_dlk18.png|300px|reaction trajectory for H2 + F]] [[File:mom_dlk18.png|300px|Momentum vs. time for H2 + F]]

The reaction trajectory shows oscillation even in the product region of this reaction. This is shown more clearly in the momentum vs. time plot.

Exothermic reactions like this can be classified as having attractive or repulsive potential energy surfaces.
By changing the momentum of for r(HH) we are able to see that this is a repulsive energy surface. The plot below demonstrates this:

Further investigation, by adjusting the momentum of r(HH) in the range -6.1 to 6.1g mol-1.pm.fs-1.

The plots show the reaction trajectory with r(HH) momentum = -6.1 and X respectively.

File:Mom dlk18.png

2020-05-22T21:14:05Z

Dlk18: dlk18

dlk18

MRD:dlk188

2020-05-22T21:12:40Z

Dlk18: /* Reaction Dynamics */

== Exercise 1 ==
===Transition state===

On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be approximately 0.00. As the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” below demonstrates the symmetry of the transition state; equal distances between A-B and B-C . A-C is double A-B.
[[File:dlk18_ex1_indistance_vs_time.png|300px|Internuclear distance vs Time for transition state of H-H-H system]]
=== MEP ===
Comment on how the ''mep'' and the trajectory you just calculated differ.

mep always resets to 0, no oscillation, shorter bc gradient =0 therefore stops once it reaches the bottom of the energy well.

Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the transition state barrier; i.e initially could be seen as reactive as the reactants do react to form products, but then the reverse reaction occurs and the trajectory is taken back to reactants. This is also shown clearly in the animation and contour plot.
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values and hence an overestimate.

== Exercise 2 ==

=== PES Inspection ===

The F-H-H system was set up with the H2 molecule approaching the Fluorine atom. The potential energy surface shows that the F + H2 reaction is exothermic, and the HF + H reaction is endothermic. This indicates that the HF bond is of higher strength than the HH bond.

Finding the Transition State:

The Transition state was estimated the same way as the previous system, though this time the transition state is asymmetric. Using Hammond's postulate and the fact that the reaction is exothermic, the (early) transition state was estimated to be X. This is confirmed by the force values X AND X and the eigenvector (omega squared values): X,X. The change in sign indicating the presence of a saddle point.

The activation energy:

The activation energy for each reaction was found in different ways.

For the HF + H reaction, an MEP calculation was performed to displace the reaction from the transition state towards the reactants. This was done using 4000 steps. The plot below demonstrates the energy displacement from the transition state and shows the energy drop into the well of pure reactant state:
The activation energy was found to be 124kj/mol approximately.

[[File:activation_dlk18.png|300px|Energy vs Time showing the displacement of transition state to reactants for HF + H]]

For the H2 + F reaction, the activation energy was found using Hammond's Postulate; kowing the reaction is exothermic, the expected activation energy would be small. This was found by displacing the distance of the HF atom 4000pm away, ensuring the energy would be that of pure reactant only in this case.
The activation energy was found to be 1 kj/mol approximately.

=== Reaction Dynamics ===

The reaction trajectory for H2 + F is plotted below:

[[File:rxn_dynamic_dlk18.png|300px|reaction trajectory for H2 + F]]

The reaction trajectory shows oscillation even in the product region of this reaction. Exothermic reactions like this can be classified as having attractive or repulsive potential energy surfaces.
By changing the momentum of for r(HH) we are able to see that this is a repulsive energy surface.
The plots show the reaction trajectory with r(HH) momentum = -6.1 and X respectively.

MRD:dlk188

2020-05-22T21:04:43Z

2020-05-22T17:50:14Z

Dlk18: /* PES Inspection */

MRD:dlk188

2020-05-22T17:49:42Z

Dlk18:

== Exercise one ==
On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be .........s the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” demonstrates this: equal distances between A-B and B-C . A-C is double A-B.

=== MEP ===
Comment on how the ''mep'' and the trajectory you just calculated differ.

mep always resets to 0, no oscillation, shorter bc gradient =0 therefore stops once it reaches the bottom of the energy well.

Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the barrier
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values and hence an overestimate.

== Exercise 2 ==

=== PES Inspection ===

The F-H-H system was set up with the H2 molecule approaching the Fluorine atom. The potential energy surface shows that the F + H2 reaction is exothermic, and the HF + H reaction is endothermic. This indicates that the HF bond is of higher strength than the HH bond.

Finding the Transition State:

The Transition state was estimated the same way as the previous system, though this time the transition state is asymmetric. Using Hammond's postulate and the fact that the reaction is exothermic, the (early) transition state was estimated to be X. This is confirmed by the force values X AND X and the eigenvector (omega squared values): X,X. The change in sign indicating the presence of a saddle point.

The activation energy:

The activation energy for each reaction was found in different ways.

For the HF + H reaction, an MEP calculation was performed to displace the reaction from the transition state towards the reactants. This was done using 4000 steps. The plot below demonstrates the energy displacement from the transition state and shows the energy drop into the well of pure reactant state:

[[Image:activation_dlk18.png|Energy vs Time showing the displacement of transition state to reactants for HF + H|Image: 100 pixels]]

The activation energy was found to be 124kj/mol approximately.

For the H2 + F reaction, the activation energy was found using Hammond's Postulate; kowing the reaction is exothermic, the expected activation energy would be small. This was found by displacing the distance of the HF atom 4000pm away, ensuring the energy would be that of pure reactant only in this case.
The activation energy was found to be 1 kj/mol approximately.

MRD:dlk188

2020-05-22T17:45:51Z

Dlk18:

== Exercise one ==
On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be .........s the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” demonstrates this: equal distances between A-B and B-C . A-C is double A-B.

=== MEP ===
Comment on how the ''mep'' and the trajectory you just calculated differ.

mep always resets to 0, no oscillation, shorter bc gradient =0 therefore stops once it reaches the bottom of the energy well.

Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the barrier
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values and hence an overestimate.

== Exercise 2 ==

=== PES Inspection ===

The F-H-H system was set up with the H2 molecule approaching the Fluorine atom. The potential energy surface shows that the F + H2 reaction is exothermic, and the HF + H reaction is endothermic. This indicates that the HF bond is of higher strength than the HH bond.

Finding the Transition State:

The Transition state was estimated the same way as the previous system, though this time the transition state is asymmetric. Using Hammond's postulate and the fact that the reaction is exothermic, the (early) transition state was estimated to be X. This is confirmed by the force values X AND X and the eigenvector (omega squared values): X,X. The change in sign indicating the presence of a saddle point.

The activation energy:

The activation energy for each reaction was found in different ways.

For the HF + H reaction, an MEP calculation was performed to displace the reaction from the transition state towards the reactants. This was done using 4000 steps. The plot below demonstrates the energy displacement from the transition state and shows the energy drop into the well of pure reactant state:

[[Image:activation_dlk18.png| Energy vs Time showing the displacement of transition state to reactants for HF + H|Image: 100 pixels]]

The activation energy was found to be 124kj/mol approximately.

For the H2 + F reaction, the

2020-05-22T15:34:05Z

Dlk18: /* PES Inspection */

MRD:dlk188

2020-05-22T15:28:25Z

Dlk18:

MRD:dlk188

2020-05-22T15:00:49Z

Dlk18:

MRD:dlk188

2020-05-22T14:02:05Z

Dlk18:

MRD:dlk188

2020-05-22T13:24:58Z

Dlk18:

On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be As the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” demonstrates this: equal distances between A-B and B-C . A-C is double A-B.

=== MEP ===
Calculations were done setting ..... and changing the momentum, and seeing the effect this had on the reaction trajectory:
{| class="wikitable"
!p1/ g.mol-1.pm.fs-1
!
{| class="wikitable"
!p2/ g.mol-1.pm.fs-1
|}
!Etot
!Reactive?
!
{| class="wikitable"
!Description of the dynamics
|}
!Illustration of the trajectory
|-
|<nowiki>-2.56</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-414.28</nowiki>
|Yes
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-4.1</nowiki>
|<nowiki>-420.10</nowiki>
|No
|
|
|-
|<nowiki>-3.1</nowiki>
|<nowiki>-5.1</nowiki>
|<nowiki>-413.98</nowiki>
|Yes
|
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.1</nowiki>
|
|No
|recrosses the barrier
|
|-
|<nowiki>-5.1</nowiki>
|<nowiki>-10.6</nowiki>
|
|Yes
|
|
|}
The results in the table

=== TST Theory ===
The transition state theory predicts that there is no re-crossing of the barrier, once the transition state is reached the reactants will follow the reaction trajectory to form the product(s) of the reaction. The results shown in the table above however demonstrate that barrier re-crossing is possible. The implications of this on the reaction rate values is that the value predicted by the Transition state theory would be higher than experimental values.

MRD:dlk188

2020-05-22T13:18:37Z

Dlk18:

MRD:dlk188

2020-05-22T13:13:37Z

Dlk18: Created page with "On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a l..."

MRD:dlk18

2020-05-19T12:18:31Z

Dlk18:

== Intro ==

== Exercise one ==

=== Transition state ===
On a potential energy surface diagram, how is the transition state mathematically defined? How can the transition state be identified, and how can it be distinguished from a local minimum of the potential energy surface?

Locating the transition state:

'''rts''' estimated at 9.77 pm , 0 momentum for H atoms. Force is reported to be As the TS is symmetric, the internuclear distances should be equal and should remain stationary at the transition state. The plot of the Internuclear Distances vs Time” demonstrates this: equal distances between A-B and B-C . A-C is double A-B.

<gallery>
Dlk18 ex1 indistance vs time.png
</gallery>