Recall that the vibrational eigenfunctions of a harmonic oscillator are orthogonal: If yj and yk belong to different electronic states as shown here, is.

Slides:

Advertisements

Similar presentations

Atomic Emission Spectra. The Electromagnetic Spectrum High frequency Short wavelength High energy lower frequency longer wavelength lower energy.

Advertisements

e-e- E n eV n = 1 ground state n = 3 0 n = ∞ n = n = 4 ionisation N.B. All energies are NEGATIVE. REASON: The maximum energy.

Early Quantum Theory and Models of the Atom

Avoiding bleed-through artifacts on the confocal microscope Fluorescent dyes are molecules that, when exposed to light of a specific range of wavelengths,

Multi-Photon Principles - topics- l Confocal complements Multi-Photon. l What is an emission event ? l Single photon event. l Stokes’ shift and what you.

OPTICAL ABSORPTION.

Atomic Spectroscopy Laboratory Science & Engineering Magnet High Mr. Puckett.

Light and Electronic Transitions. The Big Questions What is light? How is light emitted? What do electrons have to do with light? What are emission spectra?

Flame Test and the EMS. Absorption and Emission of Light in a Flame When a substance is heated in a flame, the substances electrons absorb energy from.

Emission and Absorption of Electromagnetic Energy

Electrons and Light How does the arrangement of electrons in the atom determine the color of light that it emits?

Electronic Spectra: Ultraviolet and Visible Spectroscopy Ultraviolet and visible light give rise to electronic excitations. Spectroscopy of organic.

Fluoresecent pH-dependent Lipobeads in vivo. pH changes in biology pH changes are important to several biological processes: muscle contraction, endocytosis,

Spectroscopy. Atoms and Light  Atomic electron energy levels are a source of discrete photon energies.  Change from a high to low energy state produces.

CHEMISTRY 161 Chapter 7 Quantum Theory and Electronic Structure of the Atom

Lecture 9 Vibrational Spectroscopy. Only photons of one specified wavelength are absorbed Ground state Excited state.

Introduction to Infrared Spectrometry Chap 16. Infrared Spectral Regions Table 16-1 Most used – 15.

Photochemistry Lecture 2 Fates of excited states of polyatomic molecules.

Light as a Particle. Objectives  Define a quantum  Calculate the energy of a photon  Relate photon energy to wavelength and frequency of EMR.

Lecture 4 Intramolecular energy transfer

Vibrational Spectroscopy

Spectrochemical Analysis. Electromagnetic Radiation Energy propagated by an electromagnetic field, having both particle and wave nature.

Quantization of Energy. When the atom gets excited… To help visualize the atom think of it like a ladder. The bottom of the ladder is called GROUND STATE.

IPC Friedrich-Schiller-Universität Jena 1 6. Fluorescence Spectroscopy.

Determination of fundamental constants using laser cooled molecular ions.

Electron Energy and Radiation Quantum Mechanics and Electron Movement.

Chemical Ideas 6.2 What happens when radiation intracts with matter?

Section 4.7—Light & Matter

Molecular Luminescence

The Creation of Light. How is light created? All light starts as a vibration of charged particles, electrons that move between different energy levels.

Chem Saver Pg 18 Electrons absorb energy and jump to excited state Electrons release energy as a photon and fall back to ground state.

Chapter 3. Light emitting diod

Topic #9 : Ground State vs. Excited State What is the difference between ground state and excited state electron configurations? How can we identify unknown.

Of all the transitions that are allowed, how do I figure out intensities?

Electronic Structure of Atoms Chapter 4 Electronic Structure of Atoms.

Light & Matter: Flame Test Background Information.

Electronic Spectroscopy – Emission ( ) Fluorescence is the emission of light by a molecule in the excited state Fluorescence – Decay occurs between.

CHAPTER 2 ATOMIC STRUCTURE 2.1 Bohr's atomic model 2.2 Electronic configuration.

Chem-To-Go Lesson 7 Unit 2 ENERGY OF ELECTRONS. ENERGY BASICS All energy travels in the form of a wave. Scientists measure the wavelength of a wave to.

Photochemistry Photochemistry is the study of the interaction of electromagnetic radiation with matter resulting into a physical change or into a chemical.

Physics and the Quantum Mechanical Model

Light and Electronic Transitions

Ultraviolet–visible spectroscopy UV

Early models to Quantum Model

Ultrafast Spectroscopy

3.2 Bohr’s Model of the Atom

Lecture 4 Intramolecular energy transfer

Anharmonicity In real molecules, highly sensitive vibrational spectroscopy can detect overtones, which are transitions originating from the n = 0 state.

Light and Electronic Transitions

HYDROGEN EMISSION SPECTRUM

Quantum Warmup #1 1a) Describe what is observed when salts of Li, Na, Cu, Sr and K are heated strongly in a flame. 1b) Write an essay using the word bank.

Why is the sky blue? (A) Because the oxygen in air is absorbing reddish light, so the remaining light has a bluish tinge. (B) Because blue light.

Illustration of Jablonski Diagram

Probability of Finding

M. Billings North Surry High School

Quantum Mechanical Treatment of The Optical Properties

The fingerprints of elements

Electromagnetic Radiation

Overview of spectroscopy transitions

The Creation of Light.

Why is the sky blue? (A) Because the oxygen in air is absorbing reddish light, so the remaining light has a bluish tinge. (B) Because blue light.

The Creation of Light.

The Creation of Light.

Consider the experimental evidence you just saw,

How do I get experimental information on bond lengths in simple

Atomic Spectra As atoms gain energy their electrons can be excited and absorb energy in discrete amounts called quanta and produce absorption spectrums.

Excited State vs. Ground State

Recall that the vibrational eigenfunctions of a harmonic oscillator are orthogonal: If yj and yk belong to different electronic states as shown here, is.

What is the potential energy function for a 1D Harmonic Oscillator

Presentation transcript:

Recall that the vibrational eigenfunctions of a harmonic oscillator are orthogonal: If yj and yk belong to different electronic states as shown here, is this still true? (A) Yes, because two vibrational eigenfunctions are always orthogonal. (B) No, because the potential curves are anharmonic oscillators, and two eigenfunctions of anharmonic oscillators are no longer orthogonal. (C) No, because they belong to different oscillators (different el. curves)

Recall that the vibrational eigenfunctions of a harmonic oscillator are orthogonal: If yj and yk belong to different electronic states as shown here, is this still true? (A) Yes, because two vibrational eigenfunctions are always orthogonal. No, see (C) (B) No, because the potential curves are anharmonic oscillators, and two eigenfunctions of anharmonic oscillators are no longer orthogonal. Not true! Any two non-degenerate eigenstates of the same system are orthogonal. (C) No, because they belong to different oscillators (different el. curves). Orthogonality is only given within one and the same curve.

Consider the experimental evidence you just saw, and look at the level diagram shown here. What happens after excitation with a photon energy higher than the S0  S1 energy difference if the excited dye molecule can fluoresce? (A) The molecule does not absorb. No fluorescence is detected. (B) The molecule absorbs on a vibronic transition of the S1 state with higher vibrational quanta can fluoresce back into S0 from that higher-up state. (C) The molecule absorbs into S2 or higher singlet states. From there, it quickly relaxes by other processes than photon emission into the S1(v=0) state, from where it fluoresces. (D) The molecule absorbs into S2 or higher singlet states. From there, it fluoresces. S0 (ground state) S1 S2 S3 S4

Consider the experimental evidence you just saw, and look at the level diagram shown here. What happens after excitation with a photon energy higher than the S0  S1 energy difference if the excited dye molecule can fluoresce? (A) The molecule does not absorb. No fluorescence is detected. Wrong! The experiment shows that green and all higher photon energies are absorbed. (B) The molecule absorbs on a vibronic transition of the S1 state with higher vibrational quanta can fluoresce back into S0 from that higher-up state. Wrong! The experiment shows that the wavelength (i.e. color) of the fluorescence light is the same for all excitation wavelengths. (C) The molecule absorbs into S2 or higher singlet states. From there, it quickly relaxes by other processes than photon emission into the S1(v=0) state, from where it fluoresces. → CORRECT! (Kasha’s Rule) (D) The molecule absorbs into S2 or higher singlet states. From there, it fluoresces. Wrong! The experiment shows that the wavelength (i.e. color) of the fluorescence light is the same for all excitation wavelengths. S0 (ground state) S1 S2 S3 S4