IR Spectroscopy

Exam 3 Prep

Shorter Wavelength And Longer Wavelength

A higher photon energy (E) means ______ And a lower photon energy means ______

Vibrates

What happens to bonds with the Photon type: IR?

Breaks

What happens to bonds with the Photon type: UV?

UV–vis (absorption) spectroscopy

Useful for measuring solution concentration, based on peak intensity(Quantitative, how much do we have?)

Faster Vibration And Slower Vibration

In terms of vibration, a higher photon energy (E) means ______ And a lower photon energy means ______

IR (transmission) Spectroscopy

Useful for identifying functional groups, using peak frequency or energy (in wavenumbers) (Qualitative, what do we have?)

Peak Signals

Groups of atoms vibrate at specific IR frequencies (_______________)

Bond Stretching, Angle Bending, And Rocking

Frequencies often correlate with specific motions such as:

Two atoms connected by a string

Simplest model (bond stretching):

Absorbing an IR photon And Vibrate by a spring

___________ (energy source) makes the bond ______________

Absorbing an IR Photon And Change in Dipole Moment

The ________________ depends on the relative ____________

Light Atoms (H)

IR frequencies are highest, thus greater wavenumber, for bonds with:

Triple > Double > Single

IR frequencies increase, thus greater wavenumber, with Bond Order meaning:

IR Signature

Many bonds have a distinct:

Multiple Bonds

Most functional groups have _______

Carbonyl (C=O) Groups

(= is double bond) IR spectroscopy can differentiate molecules with different: