Understanding Atom Excitation: Natural vs Triggered Movement and Photon Emission

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In summary, when an atom is exposed to white light, it will absorb certain wavelengths of light to excite its electrons. This unstable state will naturally cause the electrons to fall back to a lower energy state, emitting specific wavelengths of light. This process does not require any external triggering. This phenomenon was demonstrated by a former chemistry professor using a UV "black light" and a hotplate with liquid mercury, resulting in the shadow of mercury vapor being projected onto a fluorescent screen.
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wavingerwin
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I understand that when a particular atom is shone by white light, some corresponding spectra of white light will be absorbed by the atom to excite its electrons.

My question is, when an atom has its electrons excited, does it "naturally" tend to bring back its electrons to the ground state (or lower state) and emits photons along the way, or do we have to "trigger" the movement? (the atom tends to conserve its electrons in excitement)

Thank you!:rolleyes:
 
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Electrons tend to want to be in the lowest possible energy state. When an electron has been given the extra energy and jumped up the shell levels to another energy level, this is an unstable state for it to be in. It will naturally fall back down to the lowest possible energy level, releasing the difference between the energies as a particular wave length of light.

You do not need to induce the movement of the electron back to the ground state.
 
  • #3
v_bachtiar said:
I understand that when a particular atom is shone by white light, some corresponding spectra of white light will be absorbed by the atom to excite its electrons.
This effect was demonstrated to us by my freshman chemistry professor. He darkened the classroom, put a dish of liquid mercury on a hotplate between a UV "black light" (which emits the UV mercury lines) and a fluorescent screen. We saw the shadow of mercury vapor coming off the dish of hot mercury, like the smoke coming off a lit cigarette. (this professor is now deceased)
 
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haha... poor guy
 

What is "moving to a lower state"?

"Moving to a lower state" refers to the process of an atom or molecule transitioning from a higher energy state to a lower energy state. This can occur through a variety of mechanisms, including spontaneous emission, stimulated emission, and collisional de-excitation.

Why do atoms or molecules move to a lower state?

Atoms or molecules move to a lower state in order to release excess energy and become more stable. This energy can be in the form of heat, light, or other forms of radiation. The lower energy state is typically the ground state, which is the most stable state for an atom or molecule.

What is the significance of "moving to a lower state" in chemistry and physics?

The process of "moving to a lower state" is significant in chemistry and physics because it allows for the release of excess energy and the stabilization of atoms and molecules. This process is essential for understanding many phenomena, such as the emission of light in lasers, and is also a key concept in quantum mechanics.

Can "moving to a lower state" be controlled or manipulated?

Yes, "moving to a lower state" can be controlled and manipulated through various methods. For example, in the field of laser physics, researchers use methods such as population inversion and optical pumping to control the transition of atoms or molecules to a lower energy state. This allows for the precise emission of light at specific wavelengths.

Are there any real-world applications of "moving to a lower state"?

Yes, there are many real-world applications of "moving to a lower state" in fields such as laser technology, spectroscopy, and energy production. For example, the process of moving to a lower state is used in the creation of fluorescent light bulbs, solar panels, and medical imaging techniques like MRI. Understanding and controlling this process is essential for many modern technologies.

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