## Negative Frequency with the Rydberg Equation

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Christopher Kan 2J
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Joined: Fri Sep 25, 2015 3:00 am

### Negative Frequency with the Rydberg Equation

When using the Rydberg Equation, is it correct to get a negative frequency? If so, what does it mean/represent?

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Posts: 28
Joined: Fri Sep 25, 2015 3:00 am

### Re: Negative Frequency with the Rydberg Equation

I don't think you should be getting negative frequencies, since the definition of frequency in the context of chemistry (#of waves per second, also measured in Hz) won't make sense if it is negative. I.e., you can't have a negative number of wave per given time. However, the ENERGY TRANSITION can be negative, especially if an electron is losing energy (emitting energy).

But when you're trying to calculate the wavelength or frequency with the following equation (where energy transition is denoted as 'energy'):

wavelength = (c*h)/energy

the negative sign can be ignored, since negative/positive signs are used only to connote the idea of losing/gaining energy, but not for the actual calculation.

-- side note: wavelength= c / frequency, so if you were to calculate the frequency, you can just substitute the equation in for wavelength.--

Thus, with a positive value for energy, the wavelength or the frequency would always end up positive since the two constants, 'c' and 'h' are always positive. (c= speed of light; h=planck's constant)