According to Einstein and plank, the energy is mathematically defined as,
E= mc²
E= hʋ
De-broglie combined both the above equation.
hʋ = mc²
h c/λ = mc²
λ= h/mc ............................ (1)
The above the equation is called de-broglie equation.
According to quantum mechanics, the wave associated with the particle is characterised by wave function. The wave equation used to relate, the wavefunction and frequency is,
ψ= ψ₀ sin 2πʋt............................... (2)
Here,
ψ= wave function (or) eigen function
ψ₀ = wave amplitude
υ = Frequency of the waves
t= time (in seconds)
Differentiating equation (2) with respect to time
dψ/dt = ψ₀ cos 2πυt. 2πr
Again differentiating write the time,
d²ψ/dt² = ψ₀ (-sin2πυt). 2πr. 2πr
d²ψ/dt² = − sin2πυt. 4π²υ²
d²ψ/dt² = − 4π²υ²ψ .........................(3)
For above equation explains the wave motion of particles in motion, according to quantum mechanics,
But according to classical mechanics, the wave function motion associated with particle in motion is,
d² = c²∇²ψ .....................(4)
dt²
Combine (3) and (4)
c²∇²ψ↓ = − 4π²υ²ψ
Quantum Classical
mechanics mechanics
[ ∴υ = c/λ ]
c²∇²ψ = - 4π² c² ψ
λ²
- 4π ψ = ∇² ψ ............................ (5)
λ²
Here the λ denotes the wavelength of wave motion of particles in motion.
Substituting the value of λ from the de-broglie's equation.
- 4π² m² c² ψ = ∇² ψ .................. (6)
h²
For the particles in motion, the sum of the potential energy (v) and the kinetic energy (T) will give total energy of particles (E)
E = T + V
∴ T = 1/2 mc²
2T = mc²
X with m
2Tm = m²c² E= T+V
∴ T = E- V
2m (E-V) = m²c² .........................(7)
Substituting (7) in (6)
- 4π² 2m (E−V) ψ = ∇²ψ
h²
∇²ψ + 8π²m (E− V) ψ = 0 ........ (8)
h²
This equation is on of the form of schrodinger's equation.
Here,
∇² = laplacian operator,
[ ∇² = ∂² + ∂² + ∂ ² ]
∂x² ∂y² ∂z²
ψ= Displacement of the particles in motion (or) wave function.
m = mass of the particle
h = plank's constant
E = total energy of the particle
V = potential energy of the particle.
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