What is the correct math notation for the Coulomb Barrier?

[seattle.truth]

I am trying to find out what is the correct way to write the mathematical demarkation for the Coulomb Barrier.

You know, if I wanted to write the symbol for the radius of the coulomb barrier.

If anyone could show me it in the correct font that would be great.

NO, this isn't for homework, I am helping edit a friend's peer reviewed paper.

Thanks.

 

[seattle.truth]

Anybody? Bueller? Bueller?

Thanks in advance.

 

[Matterwave]

Uh, is it not just U=-kQ/r?

 

[seattle.truth]

Uh, is it not just U=-kQ/r?

Thank you for your response...

I found a webpage using that equation, but it doesn't explain what the U means

http://www.physics247.com/physics-homework-help/electric-potential-energy.php


I am trying to write "the radius of a coulomb barrier" as a mathematical symbol (one symbol, not an equation).

What is the symbol I should use?


Again, thank you. I know these questions sound dumb, but I really can't find it anywhere on the web. Peace