- #1
gatztopher
- 26
- 0
Homework Statement
I need to find the momentum space function for the ground state of hydrogen (l=m=0, Z=n=1)
Homework Equations
[tex]
\phi(\vec{p}) = \frac{1}{(2\pi\hbar)^{3/2}}\int e^{-i(\vec{p}\cdot\vec{r})/\hbar}\psi(\vec{r})d^3\vec{r}
[/tex]
[tex]
\psi(\vec{r})=Y(\theta,\varphi)R(r)=(\sqrt{\frac{1}{4\pi}})(2(\frac{Z}{a_{0}})^{3/2}e^{-Zr/a_{0}})
[/tex]
[tex]
d^3r=r^2dr sin\theta d\theta d\varphi
[/tex]
The Attempt at a Solution
After doing some plugging in and integrating, I get
[tex]
\phi(\vec{p})=\frac{4}{\pi}(2a_{0}\hbar)^{-3/2} \int r^2e^{-i(\vec{p}\cdot\vec{r})/\hbar}e^{-r/a_{0}}d^3r
[/tex]
And my little roadblock is simply regarding the [tex]\vec{p}\cdot\vec{r}[/tex]. I know that it's [tex]-i\hbar \nabla r[/tex] but I don't know how to calculate that, and as a result, I don't know how to carry out the integral.
One of the hints on the problem was, when using spherical coordinates, to set the polar axis along p. What might that mean?
Thanks for your help!
Last edited: