Lecture 1: Introduction to Spectroscopy

flashcards covering the basics of spectroscopy, electromagnetic radiation, photon theory, and the regions of the electromagnetic spectrum as introduced in the lecture notes.

What is spectroscopy?

The study of the interaction of matter with the electromagnetic spectrum.

Before spectroscopic techniques, how were organic compounds traditionally identified?

Through methods like chromatography, solubility, melting/boiling points, and odor.

Name some spectroscopic methods mentioned for identifying organic compounds.

Infrared (IR), Nuclear Magnetic Resonance (NMR), Ultraviolet (UV), and Mass Spectrometry (MS).

What is electromagnetic radiation?

Radiation produced by moving charged particles that can travel in a vacuum and travels at the speed of light; EM waves.

Are all electromagnetic waves longitudinal or transverse?

All electromagnetic waves are transverse.

What does wave-particle duality mean for light?

Light can behave as both a wave and a particle (photon).

What is the formula for wavelength in terms of speed and frequency?

λ = c / ν (lambda equals speed of light divided by frequency).

What is a photon?

The particle of light, a small wave-packet of EM radiation; its energy is E = hν.

What is the energy-frequency relationship for a photon?

Energy E of a photon equals h times its frequency: E = hν.

How are frequency and wavelength related when the speed of light is constant?

Frequency ν is inversely proportional to wavelength λ (ν ∝ 1/λ).

What does amplitude describe in a wave?

The wave height or strength of the oscillation.

What is the alternative expression for photon energy in terms of wavelength?

E = hc / λ (using E = hν and ν = c/λ).

List the major regions of the electromagnetic spectrum.

Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Which region of the spectrum is used to study molecular vibrations?

Infrared (IR) spectroscopy.

What does ultraviolet (UV) spectroscopy mainly probe in molecules?

Electronic transitions in molecules (UV-Vis region).

What region is associated with core electron excitation?

X-rays.

What are common uses of infrared radiation?

Night vision goggles and remote controls.

What are common uses of X-ray and gamma rays?

X-rays: medical imaging, airport security, inspecting welds; Gamma rays: food irradiation, cancer treatment, treating wood flooring.

Which region of the EM spectrum is detectable by the human eye, and which colors have the highest and lowest frequencies?

Visible light; violet has the highest frequency and red has the lowest.

What is the relationship between the energy of a photon and its wavelength (E and λ)?

E = hc/λ, derived from E = hν and ν = c/λ.