Chemistry help

empacher

have an exam tomorrow and there is one part of a Q i cant do, couldn't find anything in the notes

Describe, illustrating with appropriate examples, the gross selection rules for vibrational transitions in Raman and IR absorption spectroscopy.

In what region of the electromagnetic spectrum would you observe: 1). Electronic, 2). Pure vibrational, and 3). Pure rotational, transitions in a molecule? Which transition involves the largest energies?

What type of molecular transitions would you associate with the following regions of the electromagnetic spectrum: i) Ultra-violet to visible, ii) Microwave, and iii) Infra-red? Which transitions involve the lowest energies?


cheers for any help

krd

God sake....Don't rely on your notes.....google it.

What type of molecular transitions would you associate with the following regions of the electromagnetic spectrum: i) Ultra-violet to visible, ii) Microwave, and iii) Infra-red?

Night before the exam a bit late to be asking these questions. There is a lesson you need to learn.

Which transitions involve the lowest energies?

The one question I can answer. iii) Infra red.

thecornflake

Am I reading the whole question wrong or does it ask for what part of the spectrum rotational, vibrational and electronic transition energies can be found. Then in the next section gives three areas of the EM spectrum and asks you to link them with rotational, vibrational and electronic ?

Bit easy no ?

As far as i remember (I never liked the topic much), rotational is the lowest in terms of energy which would be the microwave answer.

Then vibrational - infra-red

then electronic - visible-UV

Also the very start of the question says "vibrational transitions in IR spectroscopy ". Please for the love of all that is Holy tell me the questions you gave are all not from the same big question ? If they are I would love to know what course you are doing.