# What is the unit of the Rydberg Constant? [duplicate]

In the image, the Rydberg constant seems to have two units. How is that possible?

• Inverse centimeters are/were a commonly used unit for spectroscopy. how-it-looks.blogspot.com/2010/07/… Jun 28 '19 at 18:14
• But why did they equate it with joules? Jun 28 '19 at 18:15

To convert between joules (units of energy) and inverse centimetres (conventional units of wavenumber) simply requires multiplication by a factor of $$hc$$. This is because
$$E = h\nu = \frac{hc}{\lambda} = hc\bar\nu$$