Hello !!!(adsbygoogle = window.adsbygoogle || []).push({});

I have a question that breaks the head to me, jejeje

In the process of photoemission, the total cross section is defined by:

[tex]

\sigma(\omega) = \frac{4\pi}{3}\alpha a_0^2 \omega \sum_{lmm_\gamma} \left| D_{lmm_\gamma}(\omega)\right|^2

[/tex]

where [tex]\alpha[/tex] is the fine-structure constant (dimentionless), [tex]a_0[/tex] is the Bohr's radius ( units meters), [tex]\omega[/tex] is the Energy of radiation (units Jules) and [tex]D_{lmm_\gamma}[/tex] are the transition coefficients expressed of the following way

[tex]

D_{lmm_\gamma}(\omega) = \sqrt{\frac{4\pi}{3}}\bigl< \psi_{lm}(k, r)\bigl| r Y_{1}^{m_\gamma}(\theta,\phi) \bigl | \psi_0(r) \Bigr>

[/tex]

where the wave function for the emitted electron is ( [tex]k = \sqrt{2E}[/tex] )

[tex]

\psi_{lm}(k, \mathbf{r}) = \frac{1}{kr}f_{lm}(kr)Y_{lm}(\theta,\phi)

[/tex]

and the wave function for the ionized orbital is

[tex]

\psi_0( r) = \frac{1}{r}\sum_{l m}\psi_{l m}(r)Y_{l}^{m}(\theta,\phi)

[/tex]

my simple question is:

What units must have each one of the involved terms so that the total cross section is expressed in barns?

Thanks !!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Photoemission in diatomic molecules

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**