To address the quantum quantum nature of molecules we add discrete energy levels to the Morse potential curve. The discrete energy levels are denoted by horizontal lines that represent the vibrational and rotational energy state of the molecule.
Both rotation and vibration are quantized, which leads to discrete energy levels. At room temperature, the lowest vibrational and rotational levels are the ones most commonly occupied. The different vibrational states are linked to the oscillatory motion of bonds.
The vibrational state of the diatomic molecule refers to the frequency at which the atoms oscillate. The frequency of molecular vibrations are in the order of 10-12 to 10-14 Hz. In this simple molecule, the only vibration mode available is along the bond. More complicated molecules have many types of vibration and stretching modes.
Only certain frequencies are allowed by selection rules for the observed bond oscillation, and is similar to what is observed with standing waves. The fundamental frequency forms a standing wave with a two nodes and a single anti-node. Only specific multiples of the fundamental frequency will result in standing waves (1f, 2f, 3f,.., etc.). Hence, there are only discrete frequencies for standing waves, just like there are discrete vibration modes for bond stretching.
Adjust the frequency of the vibration to the left by clicking the π orbitals, the vibration level directly or the selector. What happens to the potential energy? What happens to the appearance of the string? What happens to the string at the harmonic frequencies?
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Physical chemistry attempts to understand chemistry through the physical world and using instrumentation.
Molecular excitation refers to the promotion of an electron to an excited state. This particular pheomenon is extremely important for current scientific discovery, particularly in the biological sciences.
A simple harmonic oscillator displays a very particular type of periodic motion called simple harmonic motion. A common example of a simple harmonic oscillator is a spring that is compressed or stretched.
Morse potentials are used to model the interaction between two atoms in a diatomic molecule.
A diatomic molecule has only two atoms which are connected through a chemical bond. This particular diatomic molecule is double bonded.
The energy of a diatomic molecule can be approximated using a Morse Potential. Quantum effects are not discussed.
The vibrational state of the diatomic molecule refers to the frequency at which the atoms oscillate (ie. the bond stretches and compresses).
A single rotational mode is available to the diatomic molecule and involves rotation around an axis that is perpendicular to the bond axis. The energy of the rotational mode is directly related to its angular momentum.
Electromagnetic radiation is a form of that travels in waves. Specifically, electromagnetic energy travels in a transverse wave that oscillates at a certain frequency.
Like other dipoles, the transition dipole refers to a difference in charge from one location of a molecule to another. The transition dipole occurs when an electron is excited from the ground state to an excited state.
The Jablonski diagram is capable of showing the transition between ground states and excited states by using quantized Morse potentials.
Fluorescence begins with absorption and molecular excitation into an excited state. Once promoted, the electron will fall to the lowest vibrational energy within that excited state.