Spectroscopy

Question 1

spectro-

Answer 1

to look

Question 2

photo

Answer 2

light

Question 3

metry-

Answer 3

to measure

Question 4

scopy

Answer 4

to examine

Question 5

is spectrophotometry quantitative?

Answer 5

yes

Question 6

spectroscopy is qualitative?

Answer 6

yes

Question 7

highest to lowest energy light forms

Answer 7

Highest Energy: gamma rays
x-rays
UV
visible (V I B G Y O R)
IR
microwave
Lowest Energy: radio

Question 8

relationship between energy, frequency, and wavelength

Answer 8

high energy = high frequency = low wavlength

Question 9

nu = c / lambda

Answer 9

frequency = c over wavlength

Question 10

absorption of energy outcomes: removal of an electron, rotational excitation, vibrational excitation, electronic excitation ranked requiring most energy to lowest energy

Answer 10

Needs Most Energy: removal of an electron
electronic excitation
vibrational excitation
Needs Least Energy: rotational excitation

Question 11

Where does electronic excitation happen?

Answer 11

UV-Vis

Question 12

where does vibrational excitation happen?

Answer 12

IR

Question 13

where does rotational excitation happen?

Answer 13

Radio

Question 14

Which transition involves a relaxation that does not give off either a photon or heat?

Answer 14

vibrational relaxation, it can disperse the energy throughout the molecule through it bond vibrations

Question 15

similarities and differences of fluorescence and phosphorescence

Answer 15

both absorb photons, vibrational relaxation, then emit photons of a lower E
fluorescence emits from a singlet state + has no change in spin state, phosphorescence has an intersystem crossing from singlet to triplet, emits from a triplet; fluor. has faster time scale than phosph.

Question 16

ground state + photon = excited singlet state

Answer 16

absorption

Question 17

excited singlet state = ground state + photon

Answer 17

fluorescence / emission

Question 18

excited singlet state = ground state + heat

Answer 18

internal conversion

Question 19

excited singlet state = excited triplet state + heat

Answer 19

intersystem crossing

Question 20

excited triplet state = ground state + photon

Answer 20

phosphorescence / emission

Question 21

excited triplet state = ground state + heat

Answer 21

intersystem crossing

Question 22

which transitions require a change in electron spin?

Answer 22

phosphorescence and intersystem crossing; T to S or S to T

Question 23

For any fluorescence or phosphorescence process; which part involves higher energy?

Answer 23

absorption requires higher energy / shorter wavelength
emission involves lower energy / longer wavelength as there is a reduction of energy that occurs through vibrational relaxation between absorption and emission

Question 24

the difference in energy b/w ground and excited states varies based on the structure of the molecule; how does this affect absorption of the molecule?

Answer 24

differences in band gaps lead to different amount of energy required for the absorption transition to occur, each molecule will have different wavelengths where it is more likely to absorb

Question 25

what are the nonradiative types of transitions?

Answer 25

vibrational relaxation, internal conversion, and intersystem crossing

Question 26

which transitions involve photons?

Answer 26

fluorescence, phosphorescence, and absorption

Question 27

which transition has a change in spin state: intersystem crossing or internal conversion?

Answer 27

intersystem crossing