A movement generated by the action of a changeable recovery force and concerning its mean position is theoretically characterised as simple harmonic motion or simple harmonic oscillator. This motion is frictionless, and the location (trigonometric) is projected through time. Translational, vibrational, and rotational motions can be distinguished between two atoms in a diatomic molecule. Internal motions like rotation and vibration do not modify the molecule’s centre of mass, which is characterised by translational motion. The particle in a box model outlined previously can be used to model quantum translational motions. In contrast, the stiff spindle or harmonic oscillator models can be used to model rotation and vibration, respectively.
Harmonic Oscillator
A harmonic oscillator is a simple model that may be used to explain a wide range of phenomena.  A mass m on which a force acting linearly in a displacement from equilibrium acts is a simplest physical manifestation of A harmonic oscillator. Because a spring produces a linear force that is linear for tiny displacements.  The highest mass m is subjected to a force of k x acting to the right, where k is Hooke’s spring constant. The mass in the centre is in equilibrium, whereas the mass at the bottom is subjected to a force of k x to the left. It depicts a simple harmonic oscillator implementation. An oscillatory motion occurs when the body moves back and forth around a fixed point. As a result, an oscillatory motion can also be periodic but is not required.
Simple Harmonic Motion Formula
The simple harmonic motion formula can be calculated as When we pull the spring inwards, and the string exerts a force towards the equilibrium position. As a result, we can see how the spring’s force is pointing in the direction of equilibrium. The vital force is the name given to this force. Periodic motion is defined as a motion that repeats itself at regular time intervals.
Let F be the force and x be the distance between the string’s equilibrium position and the force. As a result, the restoring force is provided by F= – kx. The constant k, often termed the force constant, is used here. The Newton per meter is the unit of measurement.
Let’s say the mass of a string is m. The body’s acceleration is then:
a=Fm
 a=–k×xm
 =–ω2x
km=2ω in this case. Which we can call a simple harmonic motion formula. The time it takes for an object to complete one oscillation is called a period. The number of oscillations a particle undergoes per unit of time is the frequency of SHM. As a result, the oscillatory motion’s frequency is f=1/T.
Definition of periodic motion
In physics, the definition of periodic motion is defined as motion that occurs at regular intervals. A rocking rocker, a bounding sphere, a vibrating tuning fork, a pendulum in movement, the Planet in its orbit around the Sun, and a sea wave are examples of periodic motion. In other words, the definition of periodic motion is a motion that repeats itself at a regular time interval.
The time it takes for the motion to repeat itself is called the period (T). The period is measured in seconds.
The frequency (f) of a motion is defined as the number of times it repeats in one second. The frequency unit is Hz (Hertz). Frequency is proportional to the length of time. f= 1/T
It’s a periodic motion with a relationship between both the restoring force and the deviation from the mean position. SHM is a type of oscillation wherein motion is carried out in a straight line between two extreme points. In basic harmonic motion, a restoring force can be oriented towards the mean or the equilibrium positions. In simple harmonic motion, the mean position is indeed a stable equilibrium.
Periodic motion is a movement where an object repeats its course at regular intervals. In our daily lives, we witness several examples of periodic motion. The motion of a clock’s hands is an example of periodic motion. Periodic motion can be seen in the rocking of a cradle, swinging on a swing, or the leaves of a tree moving back and forth owing to a breeze.
Conclusion
The motion of a particle is said to be simple harmonic when it oscillates about its mean position across a straight line under the application of a force at any instant from the mean position, and the oscillating particle is termed a simple harmonic oscillator.
The harmonic oscillator exemplifies periodic motion. The atoms in a crystal are temporally dislocated from their normal positions in the structure at temperatures below 0o K due to thermal energy absorption. Inter-atmospheric forces obey Hooke’s Law act on the displaced atoms. As a result, every atom’s vibrations are identical to those of a simple harmonic oscillator.