Talk:Atomic orbital

From Wikipedia, the free encyclopedia

WikiProject Physics This article is within the scope of WikiProject Physics, which collaborates on articles related to physics.
B This article has been rated as B-Class on the assessment scale.
??? This article has not yet received an importance rating within physics.

Help with this template This article has been rated but has no comments. If appropriate, please review the article and leave comments here to identify the strengths and weaknesses of the article and what work it will need.

Contents

[edit] Re : d orbitals and above

I made the edit adding a warning to some of the links relating to orbitals - I was not logged in at the time so my user name appears as a number. Also there is a picture at the top of the article that also includes an incorrect d orbital etc - but I do not know how to edit it. Unfortunately I cannot find a link to an image of a set of 5 more correct d orbitals on the web - sorry. HappyVR 18:28, 11 February 2006 (UTC)

We need to pick a page to explain electron shells in general: Electron shell, Orbitals, Atomic orbital, Electron configuration are all valid candidates, and none of them explain the basic ideas yet

- I agree but I am not a chemist, I am more a general knowlegist. Also I am only 16 and this subject is not one i know well. - fonzy

Electron shell, Orbitals, Atomic orbital, Electron configuration and possibly periodic table block should all be merged into a single article, preferably by someone who knows what they are talking about. The Anome
I agree with this remark. This is in fact very difficult to write easy to read articles on all these topics separately. They are so strongly linked with each other! Splitting all those entries provides the reader the not untrue impression of a big mess very difficult to edit even by specialists. --131.220.68.177 07:40, 27 July 2005 (UTC)
Perhaps they should be introduced in Basics of quantum mechanics. The problem is, the only good way to learn chemistry is to learn through a series of simpler outdated models then add details and new discoveries along the way. All the encyclopedia articles just jump into the currently most accepted models, which are very intimidating and complex.

I think there needs to be a different page for each part of this. Atomic orbitals, their own page, Electron configuration, their own page, and etc. It would help separate different parts of the Atomic structure. I'm doing research on one specific part: Atomic Orbitals, and when all of the information is meshed, it keeps it from being allowed to be expanded upon. I don't know, just putting in my two cents.--- JulieRaven

I agree with User:JulieRaven - the articles need to be kept separate - they are all quite long as it is - although there is quite a lot of duplication between them I think this to be expected as they all cover closely related topics. As for a place to start the explanation of electron shells - how about with the first experimental evidence for them - I think this was Balmer/Lyman lines in the sun's spectra - this leads to (amongst others) Bohr's model of the atom (first example of a theory involving quantisation?) and eventually to quantum theory. I think it is important to include the experimental data/physical phenomana in an explanation of a model that attempts to explain it - if these lines in the spectrum hadn't been found we wouldn't have this article in the first place...HappyVR 20:49, 12 February 2006 (UTC)

[edit] Removing content

I've pulled the following content from the article, because I think that at least one of the following conditions applies: (a) It's duplicated at Molecular orbital; (b) It's false. --Smack 03:56, 14 Oct 2004 (UTC)

In the quantum-chemical treatment of molecules, it is usually necessary to express the solutions as linear combinations of one-electron functions which are centered on the nuclei of the constituent atoms of the molecule. These functions are referred to as atomic orbitals even though they may not actually be solutions of the Schrödinger equation for those atoms taken in isolation. This method is referred to as the linear combination of atomic orbitals molecular orbital method (LCAO MO method).

The orbitals used in the LCAO method are usually either exponentially decreasing from the atomic center (radial component of the form r = e − kx, referred to as Slater-type orbitals) or decreasing as a Gaussian function from the atomic center (radial component of the form r=e^{-kx^2}, referred to as Gaussian orbitals), though other forms have been used.

    • More comment: agreed it doesn't belong in atomic orbitals (a) but it is accurate (not b!). I'm gearing up to revise the various items on orbitals and chemical bonding.... --Ian 10:37, 29 Jan 2005 (UTC)

[edit] Anon edit

There was an anonymous edit correction (possibly?). I am no expert in this topic, so please check if the minor edit was factual. -- AllyUnion (talk) 10:28, 10 Dec 2004 (UTC)

Worry not. I have this page watchlisted. That was a genuine mistake on my part. I'm no expert myself, but it'll take a smarter-than-average vandal to get one past me. --Smack 01:45, 11 Dec 2004 (UTC)

[edit] Link suggestions

An automated Wikipedia link suggester has some possible wiki link suggestions for the Atomic_orbital article, and they have been placed on this page for your convenience.
Tip: Some people find it helpful if these suggestions are shown on this talk page, rather than on another page. To do this, just add {{User:LinkBot/suggestions/Atomic_orbital}} to this page. — LinkBot 01:04, 18 Dec 2004 (UTC)

[edit] orbitals, shape and energy

I've amplified the introduction to say what an orbital is, and is not, and linked to the electron configuration and periodic table pages. The former page duplicates quite a bit of this one, but why not? Having the same material in several places may not be efficient storage wise, but can help the reader. Similarly, I reckon its helpful to have large topics slpit into smaller pages, so wouldn't want to consolidate everything together. I've also clarified the description of the p and d atomic orbitals, and their relation to the orbital's energy - it isn't the shape that determines it, but the detail of the probability density in the radial direction.--Ian 10:02, 30 Jan 2005 (UTC)

[edit] Possible links for demonstrating the quantum atom

Below is a link to a video produced by astronauts at the international space station that shows wave patterns in a very large sphere of water (something not attainable on Earth). It reminded me of the various orbitals within an atom. It would be particularly useful for demonstrating the electron wave patterns of hydrogen.

http://www.youtube.com/watch?v=zaHLwla2WiI

Notice that at 0 & 180 deg. to the initial energy pulse, the oscillations resembled a p-orbital along that axis, but the globule retains the basic (lower energy) spherical shape throughout the course of its vibration, and eventually comes to rest back at that ground state (you can almost pick out the other two p-orbitals as well, but they are not well resolved. Also, the multitude of concentric rings running up and down the axis of the initial pulse seem to me to resemble one of the possible d-orbitals (dSubscript zSuperscript 2) and f-orbitals (I think it is the fSubscript x)Superscript 3Subscript - 3/5xrSuperscript 2). These patterns are all simultaneously present, oscillating from one orbital type to another and back again, or even appearing and vanishing again. I found it very interesting to see the one lobe of the p-orbital mimetic appearing in one direction, and then vanishing again as the lobe in the opposite direction appears.

These vibrational patterns appear to me to be analogous to an atom absorbing a photon, kicking an electron to a higher orbital, followed by the atom relaxing back to its ground state as it remits the photon and that orbital shape dissapears (although the possibility for the orbital to reappear is always present when the next photon interacts with it).

It would be interesting to see the result of using a more energentic pulse to initiate the globual's vibration. I suspect that at higher energy, a smaller water droplet would be ejected from the larger globual, similar to what is observed with the photoelectric effect, where only photons with sufficient energy can kick electrons from a metal plate to complete a circuit.

Many students find the entire subject to be confusing in the extreme, and seem to fixate on the idea that these orbitals are solid, tangible objects hiding under the surface of the atom like steel girders in a building). Perhaps this video could help (assuming no one here finds serious fault with my interpretation).

There are some other very interesting videos on cymatics (the study of wave behavior) given below:

1. http://www.youtube.com/watch?v=8ik6RgdoIMw (The sequence from ~ 0:43 sec to 0:50 sec reminds me of benzene, with its alternating pi-bonds, and equivalent resonance structures.)

2. http://video.google.com/videoplay?docid=2795869048702157810&q=cymatics&hl=en

3. http://video.google.com/videoplay?docid=7253148167375317006&q=cymatics&hl=en

Since I am not certain that this wiki page is the best location for any this material, I felt that placing it here for further discussion would be best.

Thanks, DF 72.48.34.162 04:21, 4 December 2006 (UTC)

[edit] Relation to the Heisenberg-Bohr-Sommerfeld Picture and Hydrogen SO(4)

The discussion regarding the shapes of orbitals is not complete until the Heisenberg picture view of the Hydrogen atom (and more generally: the Kepler problem) is included. The two sets of parameters that determine an orbit's shape and size in the classical Kepler problem (angular momentum and eccentricity/direction of closest approach) have magnitudes that assume perfectly well-defined eigenvalues in the quantum version of the Kepler problem for each orbital state; hence the shape of the orbital is, itself, well-defined. The uncertaintly actually applies to the orientation of the orbit, not its shape or size.

In the quantized problem the two vectors generate a constrained version of SO(4) (hence the term "Hydrogen SO(4)"); or E(3) for parabolic orbits, or SO(3,1) for hyperbolic orbits. Both the eccentricity e and the magnitude of the angular momentum |L| assume eigenvalues in the orbital states. The orbital shapes resulting from the eigenvalues both supersede and refine those that had historically been associated with the Bohr-Sommerfeld orbits; namely that the major axis (a) is proportional to the square of the energy number n; the semilatus rectum is proportional to 1 + l(l + 1) (in contrast to Bohr-Sommerfeld's l squared), where l is the angular momentum quantum number. The terms in the correction 1 + l to the Bohr-Sommerfeld figure arise, respectively, from the uncertainty in the direction of the closest approach, and in the components of the angular momentum.

More generally, there should be a discussion concerning the Heisenberg picture and Hydrogen SO(4) -- either directly here, or provided by a link. -- Mark, 23 October 2006 '—The preceding unsigned comment was added by 129.89.32.142 (talk • contribs).'

Hi Mark, the way you describe it here is probably too much for a high-school student (which probably use the wikipedia more to increase their knowledge than people with a degree in quantum mechanics), but I do agree, a good and complete picture is necessary. Could you write either a paragraph about this subject, or indeed maybe a new articles, e.g. something like atomic orbital shape and molecular orbital shape? I will be glad to help you with polishing, comments, but I am not really good in quantum mechanics, but hey, maybe I can learn something from it!
Could you please [[wp:sig|sign}} by typing four tildes at the end of your contribution (i.e. ~~~~). This converts to your signature automatically upon saving. Thanks! --Dirk Beetstra T C 20:19, 23 October 2006 (UTC)

[edit] Edits by User:147.231

I'm distressed by these modifications. I don't have the expertise to corroborate or dispute their factual correctness, but one thing is clear: they're inaccessible to anyone without extensive training in mathematics and quantum mechanics. Wikipedia is not a physics reference text; it's supposed to be written so as to be readable by as many people as possible. The corrections should be written into a special section, and the remainder of the article be left as it was. --Smack (talk) 02:31, 15 July 2005 (UTC)

  • I agree that we should go back to the simpler first paragraph. Talking about slater determinants right up front is way out of line. People who read this may not even know what a wavefunction is. But the rest of the changes look good, and the info in the new first paragraph can be moved down to another section. Pfalstad 03:28, 15 July 2005 (UTC)
The problem with the older first paragraph was that is was simply false. Moreover an atomic orbital is a wave function. Thus it is quite difficult to discuss about an atomic orbital without referring to the concept of wavefunction. Of course one can make it more pedagogic but pay attention not to write anything false. --131.220.68.177 12:01, 25 July 2005 (UTC)

[edit] Hydrogen-like atoms

I believe the section Hydrogen-like atoms should be moved to the article Hydrogen atom or to a new article which could be "derivation of the hydrogen atom formulae" which solution would be preferred since the article Hydrogen atom is very good as it stands and should not be expanded anymore.

Atomic orbitals are quite different from the eigenfunctions of the hydrogen atom. The hydrogen atoms are one electron atoms only and this is a big conceptual difference. Of course one can use the Hydrogen atom eigenfunctions as atomic orbitals but one does not have to. In practice one often does not! --131.220.68.177 08:23, 26 July 2005 (UTC)

Two important points:
  1. Hydrogen wavefunctions are indeed different from the wavefunctions seen in more-complex atoms, but they're an important special case, and should IMHO be retained here.
  2. Hydrogen wavefunctions are not unique to hydrogen. Ions such as He + or Li + 2 may be oddities that occur primarily in physics textbooks, but they do exist. --Smack (talk) 02:15, 27 July 2005 (UTC)
What does IMHO mean?
Of course they exist but they are usually discussed together with the hydrogen atom wavefunctions. They belong to some remark in the hydrogen atom article.
Could someone tell be why the proof of the formulae of the hydrogen atom are found in this article and not in hydrogen atom.--131.220.68.177 07:33, 27 July 2005 (UTC)
Sorry for the neologism. See Internet slang.
The partial derivation (it's neither complete nor a proof) is found here because, as I said above, these things are not unique to hydrogen. They're also found (in a somewhat more general form) in one-electron ions such as He + . Though these ions are exceeedingly rare here on earth, they probably occur in larger quantities in space, and at any rate, the natural occurrence of a substance is of little theoretical consequence. --Smack (talk) 18:14, 27 July 2005 (UTC)
OK I found that by typing IMHO on wikipedia.
The reason why this result can be found in almost all textbooks (and also in the hydrogen atom article by the way) is because the atomic orbitals used is practice are often Slater-type orbitals but with some Z different from the actual charge of the nuclei.
If it is nor complete nor a proof why must it be here? I definitively think these details belong somewhere else. --131.220.44.10 08:47, 28 July 2005 (UTC)
So, if hydrogen-like orbitals (or Slater-type, or one-electron, or whatever you want to call them) are used in LCAO, isn't that by itself justification enough to talk about them in a general article?
Why do you insist on calling this derivation a 'proof'? A proof always starts with the thing to be proven. Even if it is not used explicitly as a starting point in a series of transformations, the end result is always given beforehand.
More to the point, why must all derivations given on the wiki be complete? You still haven't given me a reason, but I can give you a list of reasons to the contrary:
  1. Most people don't care about all of the messy mathematical details, and shouldn't be forced to scroll through them.
  2. Many people who do care about the mathematical details probably already own at least one physics reference text that outlines the derivation in sufficient detail.
  3. But, you say to #1, we can put the full derivation on a separate page. To that I reply that people like you and I have more valuable things to do with our wiki-time than to code pages and pages of TeX. --Smack (talk) 00:58, 30 July 2005 (UTC)

Well I agree with you we don't need it so suppress it because what this paragraph is all about is explaining people a bright example of separation of variables which is summarized in the hydrogen atom article and can be found in any low level text book! Do you really think someone interested in atomic orbitals wants to know something about how to derive their mathematical formula in the very special case of hydrogen-like atom - information which can be found easily on wikipedia anyway --81.209.204.11 08:16, 7 August 2005 (UTC)

Sorry, what do you mean by 'it' and by 'this paragraph'?
Honestly, I don't care much more than a rat's thighbone about whether or not a particular bit of information is contained somewhere on the wiki. I often like to ask myself: should this information be contained here; does it really belong in that other place where someone has decided to put it; and how likely is it that someone will come here looking for it and not be able to find it? In my opinion, there are two good places to put that derivation: here, or in a separate article called Hydrogen-like orbital or something to that effect. --Smack (talk) 15:27, 7 August 2005 (UTC)
Sorry I agree my English was not that bright! It and this paragraph both mean the Hydrogen-like atoms paragraph. Thus I see we begin to agree : we could put this info in a new article named Hydrogen-like atom -- hydrogen-like orbital is equivalent to Slater-type orbital. I would suggest you to merge this with hydrogen atom but this is just my opinion.--81.209.204.4 15:39, 7 August 2005 (UTC)

[edit] the giguere periodic table

The giguere periodic table is a very simple table . It classifys its elements according to what orbital the electrons end in. Oh and I do'nt appreciate what you talked about about the p or s block it just not right

[edit] Circular reference - bad for newbs

The top of this article states "A less formal description of the electrons in atoms can be found at Electron configuration.", wehereas the Electron configuration article states "The discussion below presumes knowledge of material contained at Atomic orbital."!

Basically, both articles are stating that if you are new to the subject you should read the other one first. Can this please be rectified by someone who understands the subject. I expect the best solution is to rewrite the Electron Configuration article to work as a standalone introduction for newbies, and for this article to be a more technical treatment of the subject, but other solutions are possible. --HappyDog 01:29, 21 December 2005 (UTC)

I'd like to see the two articles merged into this one. - Aug-11-06 —The preceding unsigned comment was added by 12.33.19.11 (talk • contribs).
Nope, no merge, see discussion on Electronic configuration. --Dirk Beetstra T C 16:08, 11 August 2006 (UTC)

[edit] d orbitals and above

I'm still concerned that the pictures associated with this text as well as some of the links (appear to) show incorrect (ie non degenerate) d orbitals - I can't see the point of including an image for visualisation purposes if the image gives the wrong impression. I refer to [electon_orbitals.png] and also the external link "the orbitron" and "David Manthey's Orbital Viewer renders orbitals with n ≤ 30" also gives incorrect d orbitals - I can't check the other links at the moment. Previously I added a warning to the external links but that was removed.HappyVR 19:37, 17 June 2006 (UTC)

[edit] Orbital Definition

So, is an orbital a "region in which an electron may be found", or is is a "mathematical description"? There are geometric and a methematical definitions. This needs to be clearer or we are looking at a confusing start to an inherently difficult topic. Dr Thermo 19:44, 12 June 2007 (UTC)

How about "In physics and chemistry, an atomic orbital is a mathematical description of the region in which an electron may be found around a single atom." (emph mine for diff)? Baccyak4H (Yak!) 20:10, 12 June 2007 (UTC)
Yeah that sounds way better. Amit 21:15, 25 July 2007 (UTC)

[edit] History of Orbital Definition

While presenting at the 1979 Sanibel Symposium, I had the occasion to ask Per-Olov Löwdin for his definition of an orbital. Without hesitation, he told me that it was first used by Robert S. Mulliken "in 1925 as the English translation of Schroedinger's use of the German word, 'Eigenfunktion'." Mulliken had been working in Germany in 1925 with many of the founders of Quantum Mechanics and particularly in 1927 with Friedrich Hund on the beginnings of molecular orbital theory. Mulliken presented his work at that time in Physical Review. Löwdin told me to look there for the first use of a hydrogen "orbital" in English. He also agreed that a suitable definition of an orbital would be "a mathematical function that describes the wave-like behavior of an electron". I will edit the definition to reflect this usage of the term as a mathematical function, but also connect it to the more general description of an orbital as a "region of space" that can be calculated from the function. The advent of graphing calculators has enabled even high school students to grasp the definition of an orbital as a mathematical function. I invite educators to have their students graph the "simplified' 1s orbital, y = exp(-abs(Z.x)), where Z=1,2,3(Atomic Number). This simple exercise can display the effects of electronegativity and the fact that atoms and isoelectronic ions "decrease" their size in going to the right in a row in the periodic chart. The bonding and antibonding sigma MO can also be displayed by y = exp(-abs(Zx+1) + or - exp(-abs(Zx-1) . After graphing functions, students can grasp the idea of "combining" functions (atomic orbitals) to get other functions (molecular orbitals), and what is meant by the + and - signs or the red/blue, white/gray colors of the orbitals. Laburke21:13, 25 October 2007 (UTC)

[edit] Why integer solutions?

The third paragraph of the "Connection to uncertainty relation" section doesn't seem to tell me why an electron must be in a specific set of states. It basically says there are several laws that apply and more-or-less leaves it at that. (The Bohr model page similarly fails to explain why there are discrete quanta.) How is a reader to understand why an electron can't be at n=1.5? I think this article needs to explain why the wave state collapses to the states at n=1, 2, 3, .... Thanks.—RJH (talk) 16:25, 31 January 2008 (UTC)

[edit] Apparent contradiction in discussion of limitations in an electron's location

The "Connection to uncertainty relation" section states "...this does not mean that the electron could be anywhere in the universe" and concludes with the sentence "An electron's location... stops at the nucleus and before the next n-sphere orbital begins." The first sentence of the "Shapes of orbitals" section states "... a given electron, regardless of which orbital it occupies, can at any moment be found at any distance from the nucleus and in any direction due to the uncertainty principle." This apparently contradictory text will surely confuse an unknowledgeable reader. It certainly confuses me! The text of both sections needs to be amended by a subject matter expert to clear up this seeming contradiction. Ross Fraser (talk) 17:56, 18 March 2008 (UTC)

I've tried to do some of this. I eliminated the discussion of phase-space, which while correct is confusing because phase space is not a place! It's a mathematical graph of position and momentum, and although it has voxels of minimal size, these are voxels in a 6-d graph (3 dimensions of momentum, three of space), NOT volume cells in 3-space. So mentioning this as a way to limit particles in space (3-space) is bound to confuse the reader.

The basic reason Heisenberg implies a limitation to how closely you may localize bound particles in space, is that particles are waves, and the only way you can localize a wave is to localize a wave packet. Such packets need spreads in wavelength (which means momentum, in quantum mechanics). For low energy/momentum packets, the localization of the particle and wave-packet becomes bad, and thus the packet is large, and that's why the electron can't be found at any location smaller than a certain range of distances from the nucleus. But this is a property of all kinds of waves, as Bohr pointed out. The Heisenberg relationship just gives the scale of localization, once particles are connected with wave packets. Born supplies the last connection, with how you decide the connection of particle and wave: the complex congugate of the wave in any volume gives the probability density of finding the particle within that volume. SBHarris 02:02, 3 May 2008 (UTC)