How do I properly normalize a wave function with given real functions?

In summary: And then use those values to find N?In summary, the problem asks to normalize a given function with respect to the three real functions ψ1,ψ2, and ψ3, which are assumed to be normalized and orthogonal. The normalization condition is given as N2 Integral[/ψ/2 dx] = 1. To solve, substitute the given function into the integral and evaluate it, using the fact that the ψi's are orthogonal to each other. Then, use the resulting values to find N.
  • #1
ReidMerrill
66
2

Homework Statement


"assume that the three real functions ψ1,ψ2, and ψ3 are normalized and orthogonal. Normalize the following function"

ψ1 - ψ21/(sqrt2) + ψ3sqrt(3)/sqrt(6)

Homework Equations


This is for a physical chemistry class. I haven't seen an example like this. All that is in our textbook is that integral[ /ψ/2dT] needs to equal 1 which is accomplished by adjusting N so N2 Integral[ /ψ/2dx] =1

The Attempt at a Solution


Is this correct? What range do I integrate it over? no x values are given.Any help will be greatly appreciated!
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  • #2
ReidMerrill said:

Homework Statement


"assume that the three real functions ψ1,ψ2, and ψ3 are normalized and orthogonal. Normalize the following function"

ψ1 - ψ21/(sqrt2) + ψ3sqrt(3)/sqrt(6)

Homework Equations


This is for a physical chemistry class. I haven't seen an example like this. All that is in our textbook is that integral[ /ψ/2dT] needs to equal 1 which is accomplished by adjusting N so N2 Integral[ /ψ/2dx] =1

The Attempt at a Solution

[/b]
Is this correct? What range do I integrate it over? no x values are given.
Is what correct? You haven't shown any work.

The readability of your post would improve if you use LaTeX. Here's a primer: https://www.physicsforums.com/help/latexhelp/.
 
  • #3
vela said:
Is what correct? You haven't shown any work.

The readability of your post would improve if you use LaTeX. Here's a primer: https://www.physicsforums.com/help/latexhelp/.
I don't know why all my subscripts disappeared.

ψ1 - ψ2 1/(sqrt6) + ψ3 sqrt(3)/sqrt(6)

In the book it says that to normalize a function you need to adjust N so that
N2 Integral [/ψ/2 dx] =1

I don't know how I'd apply that to this question
 
  • #4
In this problem, you have ##\psi(x) = N\left(\psi_1 - \frac{1}{\sqrt{6}} \psi_2 + \frac{\sqrt{3}}{\sqrt{6}}\psi_3\right)##. (Are you sure about that state? It's written a bit strangely, i.e., ##\sqrt{3}/\sqrt{6} = 1/\sqrt{2}##.)
 
  • #5
vela said:
In this problem, you have ##\psi(x) = N\left(\psi_1 - \frac{1}{\sqrt{6}} \psi_2 + \frac{\sqrt{3}}{\sqrt{6}}\psi_3\right)##. (Are you sure about that state? It's written a bit strangely, i.e., ##\sqrt{3}/\sqrt{6} = 1/\sqrt{2}##.)

That's how it's written in the book.

Since x isn't in the function
vela said:
In this problem, you have ##\psi(x) = N\left(\psi_1 - \frac{1}{\sqrt{6}} \psi_2 + \frac{\sqrt{3}}{\sqrt{6}}\psi_3\right)##. (Are you sure about that state? It's written a bit strangely, i.e., ##\sqrt{3}/\sqrt{6} = 1/\sqrt{2}##.)

That's just how it's written. So when I integrate that with respect to x i get N(ψ1 - ψ2 1/(sqrt6) + ψ3 sqrt(3)/sqrt(6))x +C
Did I integrate that correctly? And if so what do I do from here?
 
  • #6
Remember that ##\psi_1##, ##\psi_2##, and ##\psi_3## are functions of ##x##. You said the normalization condition is
$$\int_{-\infty}^\infty \psi^2\,dx = 1.$$ You want to substitute the expression you're given for ##\psi## and evaluate the integral.

Think about what it means when you're told that the ##\psi_i##'s are normalized and orthogonal to each other.
 
  • #7
vela said:
Remember that ##\psi_1##, ##\psi_2##, and ##\psi_3## are functions of ##x##. You said the normalization condition is
$$\int_{-\infty}^\infty \psi^2\,dx = 1.$$ You want to substitute the expression you're given for ##\psi## and evaluate the integral.
Ohhh! I did it as an indefinite integral. So, just to clarify, I need to plug in the whole original equation into the integral?
 

FAQ: How do I properly normalize a wave function with given real functions?

What is a wave function?

A wave function is a mathematical representation of a quantum system that describes its properties, such as position, momentum, and energy, at a given time.

Why is normalizing a wave function important?

Normalizing a wave function ensures that the total probability of finding the system in any possible state is equal to 1. This is a fundamental principle of quantum mechanics and allows for accurate predictions of the system's behavior.

How do you normalize a wave function?

To normalize a wave function, you must find the normalization constant, which is the square root of the integral of the absolute value of the wave function squared over all possible values. Then, you divide the wave function by this constant to obtain a normalized wave function.

What happens if a wave function is not normalized?

If a wave function is not normalized, it does not accurately represent the system and can lead to incorrect predictions. It also violates the principle of conservation of probability, which is a fundamental principle of quantum mechanics.

Can a wave function be normalized to a value other than 1?

No, the normalization constant must be chosen so that the total probability is equal to 1. This is a fundamental principle of quantum mechanics and cannot be changed.

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