[peterjones]

Naphthalene has an intense maxima at λ= 370nm. This absorption is understood to be one of the
pi -> pi^*. How do you determine the energy gap in eV for this transition?

[Borek]

You have to show your attempts at solving the question to receive help. This is a forum policy.

This is basically about converting wavelength to energy. What related formulas do you know?

[peterjones]

You have to show your attempts at solving the question to receive help. This is a forum policy.

This is basically about converting wavelength to energy. What related formulas do you know?

Well, thats reasonable. Its a bit late, now. so I'll struggle with this more tomorrow morning. But can you tell me, if I'm on the right track? the formula that comes to mind would be E=h times c / wavelength. The answer I get is 6.1425456e-25 Volts. then to convert to eV its 1 eV = 1 volt * 1/electron charge. thus its  6.1425456e-25 x1/ ( 1.60217657 × 10-19 coulombs) thus my final answer is 0.00000383387 or 3.73 x 10 ^-6 eV. Or am I totally wrong?

I feel like I am not taking into account the two energy levels, if I use that equation.

[Borek]

The answer I get is 6.1425456e-25 Volts

Good start, but it is definitely not volts. Watch your units!

I feel like I am not taking into account the two energy levels, if I use that equation.

You do. You just jump directly to the difference between these energy levels instead of treating each one separately.

[peterjones]

The answer I get is 6.1425456e-25 Volts

Good start, but it is definitely not volts. Watch your units!

I feel like I am not taking into account the two energy levels, if I use that equation.

You do. You just jump directly to the difference between these energy levels instead of treating each one separately.

 By the way, I believe I got it. besides getting the wrong units, I also used the speed of sound instead of the speed of light. I don't know why I did that. But I got my answer, I believe it should be 3.35 eV