# Examples

## or how-to's

### 1 Introduction

This page contains an overview of ASE examples.

### 3 Pair-potential examples

The examples here use the simple calculator for the force and energy calculations.

#### 3.2 Calculating the atomization energy

This example calculates the atomization energy of N_{2} using
different units.

N2

#### 3.3 Binding energy of N_{2} on a Ru(001) surface

The binding energy is calculated in the ontop configuration with and without surface relaxations. The Ru surface is a two layer slab. The top layer is found to relax slightly inward.

N2Ru

N2Ru-relax

#### 3.4 Dissociation of N_{2} on Ru(001)

For these calculations we freeze the Ru surface. Initial and final states:

The nudged elastic band method is used to find the minimum energy path from the molecular to the atomic state. Alternatively the climbing image nudged elastic band method can be activated by adding:

band.SetClimb('yes')

after the `band` object is created.

The molecular state used for the initial state is taken to be parallel to the surface. The barrier is found to be 10 eV, which is completely cracy! This shows that one should only use the simple calculator as a toy for testing and demonstration purposes.

The figur below show the resulting barriere:

#### 3.5 Dissociation of N_{2} on Ru(001) using the Adaptive Nudged Elastic Band method

In this example the dissociation of N_{2} on Ru(001) is done using the
Adaptive Nudged Elastic Band.

The figur below show the resulting barriere:

#### 3.6 Association of N_{2} on Ru(001) using constraints

Here we start with the final state from above. We slowly decrease the
N_{2} bond length in steps of 0.1 � At each step, the energy is
minimized with a constraint on the bond length.

N2Ru-association