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Wave-functions help!

Ψ1 = sin(𝑘𝑥)

and

Ψ2 = e^𝑖𝑘𝑥 = 𝑐𝑜𝑠(𝑘𝑥) + 𝑖sin(𝑘𝑥)

(i) Determine the action of the linear momentum operator (𝑝̂𝑥 = 𝑖ℏ 𝑑⁄𝑑𝑥) on each wavefunction.

Not sure how to do this
thank you
Original post by PencilPot!
Ψ1 = sin(𝑘𝑥)

and

Ψ2 = e^𝑖𝑘𝑥 = 𝑐𝑜𝑠(𝑘𝑥) + 𝑖sin(𝑘𝑥)

(i) Determine the action of the linear momentum operator (𝑝̂𝑥 = 𝑖ℏ 𝑑⁄𝑑𝑥) on each wavefunction.

Not sure how to do this
thank you


apply the operator to each wavefunction, as it says in the question:

𝑝̂ Ψ1 = 𝑖ℏ 𝑑⁄𝑑𝑥 (sin(𝑘𝑥)) = 𝑖ℏ 𝑑(sin(𝑘𝑥)) ⁄𝑑𝑥
now do the maths (ie differentiate sin(kx) wrt x and you are done with the first one :smile:
Reply 2
Original post by MexicanKeith
apply the operator to each wavefunction, as it says in the question:

𝑝̂ Ψ1 = 𝑖ℏ 𝑑⁄𝑑𝑥 (sin(𝑘𝑥)) = 𝑖ℏ 𝑑(sin(𝑘𝑥)) ⁄𝑑𝑥
now do the maths (ie differentiate sin(kx) wrt x and you are done with the first one :smile:


Thank you very much!
Original post by PencilPot!
Thank you very much!


assuming you've managed both, I'd say it's worth making a comment about whether or not each wavefunction corresponds to an eigenstate of the momentum operator.

I assume you're pretty new to quantum mechanics, so if you have any questions about what those things mean then do ask :smile:
Reply 4
Original post by MexicanKeith
assuming you've managed both, I'd say it's worth making a comment about whether or not each wavefunction corresponds to an eigenstate of the momentum operator.

I assume you're pretty new to quantum mechanics, so if you have any questions about what those things mean then do ask :smile:


Haha! that was the next question - Atkins is quite good at explaining this part

Yep, I've only just started Quantum... :redface:

And thank you!

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