Sentences with phrase «electrons in the atoms which»

«Light from the sun excites electrons in the atoms which constitute the brick wall.

Not exact matches

For example, when physicists explain the electrical conductivity of metals in terms of the «band structure» of the energy levels of the electrons in a crystal lattice of atoms, to which of the four causes does that correspond?

In this sense an atom is more complex than an electron, a molecule more complex than an atom, and a living cell more complex than the highest chemical nuclei of which it is composed, the difference depending (on this I insist) not only on the number and diversity of the elements included in each case, but at least as much on the number and correlative variety of the links formed between these elementIn this sense an atom is more complex than an electron, a molecule more complex than an atom, and a living cell more complex than the highest chemical nuclei of which it is composed, the difference depending (on this I insist) not only on the number and diversity of the elements included in each case, but at least as much on the number and correlative variety of the links formed between these elementin each case, but at least as much on the number and correlative variety of the links formed between these elements.

Every year we read more of the unimaginably minute particles such as electrons, protons, positrons, mesons, and others named and described in quick succession as science advances, which form the outer particles and the inner nuclei of the atom.

We will be concerned, however, with mental models of systems which for various reasons can not be represented by replicas, such as the economy of a nation, the electrons in an atom or the biblical God.

The history of science provides many examples of this combination of analogy and innovation in the creation of models which were useful in generating theories.4 The «Bohr model» of the atom, in which «planetary» electrons revolve in orbits around a central nucleus, resembles the solar system in certain of its dynamical properties; but the key assumption of quantum jumps between orbits had no classical parallel at all.

For example, the presence of hydrogen and methane are clues that the chemical environment of the fluid in which the diamond crystallized was one in which the metal atoms could easily gain electrons and disengage from carbon atoms.

Each hydrogen atom, made up of just a single proton and electron, can be found in two slightly different states: a higher energy state in which the electron and proton essentially spin in the same direction, and a lower energy state in which they spin in opposite directions.

There are basically two types of lines, those produced by collisions between the atoms or ions and the electrons in the surrounding gas, which are called collision lines, and which are very bright for elements such as oxygen, nitrogen and neon, and lines which are produced when ions capture free electrons, which are called recombination lines, and which are bright only for those gases with the highest abundances in the interstellar medium: hydrogen and helium.

That is the unimaginably short time scale on which processes such as the motion of an electron in an atom can be studied.

As its sharp - tipped probe scans a surface, the extent to which electrons «tunnel» between the tip and surface indicates changes in height caused by the presence of atoms.

The atomic size and structure of nitrogen make it an excellent choice for this purpose because it can fit naturally into a strong network of carbon atoms by creating bonds (sp2) in which electrons are shared by the whole network.

But for electrons, quarks (which combine to form the protons and neutrons in atoms), and other particles, the Higgs field is like an infinite, sticky ocean.

He chipped off a gram piece and put it under an electron microprobe, which uses an electron beam to excite atoms in the rock's minerals.

Ionizing radiation is a type of particle radiation in which an individual particle (for example, a photon, electron, or helium nucleus) carries enough energy to ionize an atom or molecule (that is, to completely remove an electron from its orbit).

And some of those iron atoms would thereupon fluoresce, emitting X-rays of their own — not over the whole band this time but at a single precise line in the energy spectrum: 6.4 kilo - electron volts, which is the energy an electron loses when it falls from one shell in an iron atom to a lower one.

Among other things, they can now better predict the behavior of electrons in graphene, a flat sheet of carbon just a single atom thick, which acts like a strange metal under certain conditions.

Cell phones use non-ionizing radiation, which differs from the ionizing radiation of x-rays and radioactive material in that it does not have enough energy to knock around — or ionize — electrons or particles in atoms.

Doctoral student Florian Vogel and Dr. Nelia Wanderka from the HZB Institute of Applied Materials have elegantly combined two methods to accomplish this: transmission electron microscopy (TEM) and atom probe tomography (APT), which they carried out in collaboration with colleagues from the University of Münster.

But in rare cases molecules with an even number of electrons can behave like radicals, because the arrangement of their atoms prevents all the electrons from finding partners with which to pair up.

PV materials operate using a different principle, in which photons knock electrons from the atoms of certain materials.

This material, in which carbon substitutes for some of the lattice oxygen atoms, absorbs light at wavelengths below 535 nanometers and has a lower band - gap energy than rutile (2.32 versus 3.00 electron volts).

They then exposed the evolving quantum system to a third laser beam to try and excite the atoms into what is known as a Rydberg state — a state in which one of an atom's electrons is excited to a very high energy compared with the rest of the atom's electrons.

Dawson is an expert on the interactions of lasers with plasma, the high - energy state of matter in which electrons are no longer bound in atoms, but move around independently of the positive ions they leave behind.

In the studied model system, X-rays produce the doubly - charged particle (Ne2 +), which catches an electron from one of the neighboring atoms (Kr), transferring the energy to the other and releasing another electron.

Analysis of phase - change materials showed that they work because of a particular kind of chemical bonding, called resonant bonding — a type of bond in which electrons flip back and forth between several adjacent atoms.

Others, however, think the chemical change can be explained in a more conventional picture, in which the electrons hop from atom to atom on the DNA rather than tunneling down the helix in one step.

They also found that lanthanum and arsenic atoms separated platinum layers from each other in a way, they speculate, which weakens the interaction between platinum electrons, allowing them to flow more freely and resulting in the superconducting property.

To achieve this the researchers took advantage of the manner in which Fe atoms move across the surface of graphene when irradiated by electrons in a transmission electron microscope (TEM).

But whereas those materials were made up of covalent bonds — in which pairs of atoms share electrons — these 2 - D metals are composed of metallic bonds, where electrons flow more freely among atoms.

One of the most ubiquitous is the «octet rule,» which states that each atom in a molecule that is produced by a chemical reaction will have eight outer orbiting electrons.

The results give researchers a potential new, solid - state tool for «attosecond science,» which explores processes like the motions of electrons in atoms and the natural vibrations of molecules.

Part of the difficulty is a process called photoionization, in which the high - energy photons conveying the x-rays strip away electrons from atoms within the accretion disk.

This results in defects in the lattice structure: some few carbon atoms — fewer than 1 % — separate from the lattice and are replaced with nitrogen atoms, which bring along additional electrons.

Scientists usually get around this problem by studying electrons within certain neutral atoms and molecules, in which internal fields far stronger than any external field can be induced.

«Atoms with magnetic properties disrupt the energy levels of electrons in a quantum dot, which affects how they interact with light.

Rather than processing and storing information as bits in transistors or memories, which limit information to the binary» 1» or» 0», quantum computers would instead use quantum systems, such as atoms, ions, or electrons, as «qubits» to process and store «quantum information» in, which can be in an infinite number of combinations of» 1 and 0».

And some of those ironatoms would thereupon fluoresce, emitting X rays of their own — not overthe whole band this time but at a single precise line in the energyspectrum: 6.4 kilo - electron volts, which is the energy an electronloses when it falls from one shell in an iron atom to a lower one.

After breaking away from the molecule in the strong laser field, the electron returned and was scattered on a molecular ion, which resulted in the molecule dissociation into a positive nitrogen ion and an oxygen atom.

They propose that cosmic rays contribute to ozone depletion through their interactions with human - made chlorofluorocarbons (CFCs) in the atmosphere: electrons created by cosmic rays break down CFC molecules, leading to the production of chorine atoms, which in turn break down ozone.

Unlike regular polymers like the polystyrene that vending machines cups are made from, or the clear polycarbonate that CDs are pressed with, the molecules in the new rubbery polymers are not linked by strong covalent bonds — which involve atoms sharing electrons.

But thanks to an eerie quantum effect known as superposition — which allows an atom, electron or other particle to exist in two or more states, such as «spinning» in opposite directions at once — a single qubit made of a particle in superposition can simultaneously encompass both digits.

An added complexity is that the electrons in the plasma have a much higher energy than the ionized atoms from which the electrons originated.

This turned them into Rydberg atoms, in which the electrons are in high - energy states and so orbit further away from the positively - charged nucleus.

Scientists had already suggested that, close to the black hole, the flat accretion disc puffs up into a hot plasma, in which electrons are stripped from their host atoms.

On top of the graphene is a very thin layer, just a few atoms thick, of boron nitride, which protects the electrons in the graphene from outside influences.

Laser physicists at LMU Munich and the Max Planck Institute of Quantum Optics (MPQ) have now measured the duration of such a phenomenon — namely that of photoionization, in which an electron exits a helium atom after excitation by light — for the first time with zeptosecond precision.

The surprising calculation involves the energies of the cloudlike orbitals, like this one, in which the electron in a hydrogen atom hovers.

Electrons within a target atom are first excited by a photon contained within the pump pulse, which is then followed after a short delay by a second photon in a probe pulse.

Through calculations and computer simulations, Atwater's team demonstrated that the trick to upping a material's thirst for light is to create more «optical states» for the light to occupy — which are like slots that can accept light with a certain wavelength, similar to the energy levels of electrons in atoms.