resonance

Examples of resonance in the following topics:

• Notes

• Resonance

  • Resonance structures depict possible electronic configurations; the actual configuration is a combination of the possible variations.
  • This intermediate has an overall lower energy than each of the possible configurations and is referred to as a resonance hybrid.
  • Therefore, three valid resonance structures can be drawn.
  • Sometimes, resonance structures involve the placement of positive and negative charges on specific atoms.
  • Because atoms with electric charges are not as stable as atoms without electric charges, these resonance structures will contribute less to the overall resonance structure than a structure with no charges.

• Resonance in RLC Circuits

  • Resonance is the tendency of a system to oscillate with greater amplitude at some frequencies than at others.
  • $\nu_0$ is the resonant frequency of an RLC series circuit.
  • Resonance in AC circuits is analogous to mechanical resonance, where resonance is defined as a forced oscillation (in this case, forced by the voltage source) at the natural frequency of the system.
  • A variable capacitor is often used to adjust the resonance frequency to receive a desired frequency and to reject others. is a graph of current as a function of frequency, illustrating a resonant peak in Irms at $\nu_0 = f_0$.
  • Both have a resonance at f0, but that for the higher resistance is lower and broader.

• NMR and MRIs

  • Magnetic resonance imaging is a medical imaging technique used in radiology to visualize internal structures of the body in detail.
  • Magnetic resonance imaging (MRI), also called nuclear magnetic resonance imaging (NMRI) or magnetic resonance tomography (MRT), is a medical imaging technique used in radiology to visualize internal structures of the body in detail.
  • MRI utilized the property of nuclear magnetic resonance (NMR) to image the nuclei of atoms inside the body.
  • This electromagnetic field has just the right frequency (known as the resonance frequency) to become absorbed and then reverse the rotation of the hydrogen protons in the magnetic field.

• Forced Vibrations and Resonance

  • The phenomenon of driving a system with a frequency equal to its natural frequency is called resonance.
  • The phenomenon of driving a system with a frequency equal to its natural frequency is called resonance.
  • It is interesting that the widths of the resonance curves shown in depend on damping: the less the damping, the narrower the resonance.
  • In all of these cases, the efficiency of energy transfer from the driving force into the oscillator is best at resonance.
  • Heavy cross winds drove the bridge into oscillations at its resonant frequency.

• Acidity of Phenols

  • A similar set of resonance structures for the phenolate anion conjugate base appears below the phenol structures.
  • The resonance stabilization in these two cases is very different.
  • An important principle of resonance is that charge separation diminishes the importance of canonical contributors to the resonance hybrid and reduces the overall stabilization.
  • An energy diagram showing the effect of resonance on cyclohexanol and phenol acidities is shown below.
  • The additional resonance stabilization provided by ortho and para nitro substituents will be displayed in the third diagram above.

• Standing Waves in Air Columns

  • We use specific terms for the resonances in any system.
  • The lowest resonant frequency is called the fundamental, while all higher resonant frequencies are called overtones.
  • Now let us look for a pattern in the resonant frequencies for a simple tube that is closed at one end.
  • The resonant frequencies of a tube closed at one end are:
  • Simple resonant cavities can be made to resonate with the sound of the vowels, for example.

• Resonance

  • Likewise, the structure of nitric acid is best described as a resonance hybrid of two structures, the double headed arrow being the unique symbol for resonance.
  • The above examples represent one extreme in the application of resonance.
  • The application of resonance to this case requires a weighted averaging of these canonical structures.
  • The basic principles of the resonance method may now be summarized.
  • The stability of a resonance hybrid is always greater than the stability of any canonical contributor.

• Establishing a resonating frame for businesses

• Reactions of Fused Benzene Rings

  • Naphthalene is stabilized by resonance.
  • Three canonical resonance contributors may be drawn, and are displayed in the following diagram.
  • From heats of hydrogenation or combustion, the resonance energy of naphthalene is calculated to be 61 kcal/mole, 11 kcal/mole less than that of two benzene rings (2 * 36).
  • As expected from an average of the three resonance contributors, the carbon-carbon bonds in naphthalene show variation in length, suggesting some localization of the double bonds.