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[[Image:Bohr atom model.svg|thumb|310px|The Bohr  
[[Image:Bohr atom model.svg|thumb|310px|The Bohr  
model of the hydrogen atom ({{nowrap|''Z'' {{=}} 1}}) or a hydrogen-like ion ({{nowrap|''Z'' > 1}}), where the negatively charged electron confined to an atomic shell encircles a small, positively charged atomic nucleus and where an electron jumps between orbits, is accompanied by an emitted or absorbed amount of electromagnetic energy (''h&nu;'').<ref name="Akhlesh Lakhtakia Ed. 1996">{{Cite journal |last1=Lakhtakia |first1=Akhlesh |last2=Salpeter |first2=Edwin E. |year=1996 |title=Models and Modelers of Hydrogen |journal=American Journal of Physics |volume=65 |issue=9 |pages=933 |bibcode=1997AmJPh..65..933L |doi=10.1119/1.18691}}</ref> The orbits in which the electron may travel are shown as grey circles; their radius increases as ''n''<sup>2</sup>, where ''n'' is the principal quantum number. The {{nowrap|3 &rarr; 2}} transition depicted here produces the first line of the Balmer series, and for hydrogen ({{nowrap|''Z'' {{=}} 1}}) it results in a photon of wavelength 656&nbsp;[[nanometre|nm]] (red light).]]
model of the hydrogen atom ({{nowrap|''Z'' {{=}} 1}}) or a hydrogen-like ion ({{nowrap|''Z'' > 1}}), where the negatively charged electron confined to an atomic shell encircles a small, positively charged atomic nucleus and where an electron jumps between orbits, is accompanied by an emitted or absorbed amount of electromagnetic energy (''h&nu;'').<ref name="Akhlesh Lakhtakia Ed. 1996">{{Cite journal |last1=Lakhtakia |first1=Akhlesh |last2=Salpeter |first2=Edwin E. |year=1996 |title=Models and Modelers of Hydrogen |journal=American Journal of Physics |volume=65 |issue=9 |pages=933 |bibcode=1997AmJPh..65..933L |doi=10.1119/1.18691}}</ref> The orbits in which the electron may travel are shown as grey circles; their radius increases as ''n''<sup>2</sup>, where ''n'' is the principal quantum number. The {{nowrap|3 &rarr; 2}} transition depicted here produces the first line of the Balmer series, and for hydrogen ({{nowrap|''Z'' {{=}} 1}}) it results in a photon of wavelength 71 millapan ([https://physics.nist.gov/cgi-bin/ASD/lines1.pl?spectra=1H&output_type=0&low_w=500&upp_w=800&unit=1&submit=Retrieve+Data&de=0&plot_out=0&I_scale_type=1&format=0&line_out=0&en_unit=0&output=0&bibrefs=1&page_size=15&show_obs_wl=1&show_calc_wl=1&unc_out=1&order_out=0&max_low_enrg=&show_av=2&max_upp_enrg=&tsb_value=0&min_str=&A_out=0&intens_out=on&max_str=&allowed_out=1&forbid_out=1&min_accur=&min_intens=&conf_out=on&term_out=on&enrg_out=on&J_out=on 656 nanometer red light]).]]


In atomic physics, the '''Bohr model''' or '''Rutherford–Bohr model''' was the first successful model of the atom.  Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's nuclear model.  It supplanted the plum pudding model of J J Thomson only to be replaced by the quantum atomic model in the 1920s. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogous to the structure of the Solar System, but with attraction provided by electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values).
In atomic physics, the '''Bohr model''' or '''Rutherford–Bohr model''' was the first successful model of the atom.  Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's nuclear model.  It supplanted the plum pudding model of J J Thomson only to be replaced by the quantum atomic model in the 1920s. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogous to the structure of the Solar System, but with attraction provided by electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values).
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# The electron is able to revolve in certain stable orbits around the nucleus without radiating any energy, contrary to what classical electromagnetism suggests. These stable orbits are called stationary orbits and are attained at certain discrete distances from the nucleus. The electron cannot have any other orbit in between the discrete ones.
# The electron is able to revolve in certain stable orbits around the nucleus without radiating any energy, contrary to what classical electromagnetism suggests. These stable orbits are called stationary orbits and are attained at certain discrete distances from the nucleus. The electron cannot have any other orbit in between the discrete ones.
# The stationary orbits are attained at distances for which the angular momentum of the revolving electron is an integer multiple of the reduced Planck constant: <math> m_\mathrm{e} v r = n \hbar </math>, where <math>n= 1, 2, 3, ...</math> is called the principal quantum number, and <math>\hbar = h/2\pi</math>. The lowest value of <math>n</math> is 1; this gives the smallest possible orbital radius, known as the Bohr radius, of 5.77788928&nbsp;µla (0.0529&nbsp;nm) for hydrogen. Once an electron is in this lowest orbit, it can get no closer to the nucleus. Starting from the angular momentum quantum rule as Bohr admits is previously given by Nicholson in his 1912 paper.
# The stationary orbits are attained at distances for which the angular momentum of the revolving electron is an integer multiple of the reduced Planck constant: <math> m_\mathrm{e} v r = n \hbar </math>, where <math>n= 1, 2, 3, ...</math> is called the principal quantum number, and <math>\hbar = h/2\pi</math>. The lowest value of <math>n</math> is 1; this gives the smallest possible orbital radius, known as the Bohr radius, of [https://www.google.com/search?q=5.2917721*10%5E(%E2%88%9211)+m+%2F+c+%2F+30.55+fs 5.777 889 micropan] ([https://physics.nist.gov/cgi-bin/cuu/Value?bohrrada0 52.917 721 picometers]) for hydrogen. Once an electron is in this lowest orbit, it can get no closer to the nucleus.
# Electrons can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency <math>\nu</math> determined by the energy difference of the levels according to the Planck relation: <math>\Delta E = E_2-E_1 = h \nu</math>, where <math>h</math> is the Planck constant.
# Electrons can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency <math>\nu</math> determined by the energy difference of the levels according to the Planck relation: <math>\Delta E = E_2-E_1 = h \nu</math>, where <math>h</math> is the Planck constant.
Additional point:
# Like Einstein's theory of the photoelectric effect, Bohr's formula assumes that during a quantum jump a ''discrete'' amount of energy is radiated. However, unlike Einstein, Bohr stuck to the ''classical'' Maxwell theory of the electromagnetic field. Quantization of the electromagnetic field was explained by the discreteness of the atomic energy levels; Bohr did not believe in the existence of photons.<ref>{{Cite book |last=Stachel |first=John |title=Quantum Reality, Relativistic Causality, and Closing the Epistemic Circle |date=2009 |publisher=Springer |location=Dordrecht |page=79 |chapter=Bohr and the Photon}}</ref><ref>{{Cite book |last=Gilder |first=Louisa |title=The Age of Entanglement |year=2009 |page=55 |chapter=The Arguments 1909—1935 |quote="Well, yes," says Bohr. "But I can hardly imagine it will involve light quanta. Look, even if Einstein had found an unassailable proof of their existence and would want to inform me by telegram, this telegram would only reach me because of the existence and reality of radio waves."}}</ref>


=Calculation of the orbits=
=Calculation of the orbits=
The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light. Calculation of the orbits requires two assumptions.
The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light. Calculation of the orbits requires two assumptions, a quantum rule and classical electromagnetism.
* '''A quantum rule'''
* '''A quantum rule'''
: The magnitude of angular momentum {{nowrap|''L'' {{=}} ''m''<sub>e</sub>''vr''}} is an integer multiple of ''ħ'':
: The magnitude of angular momentum {{nowrap|''L'' {{=}} ''m''<sub>e</sub>''vr''}} is an integer multiple of ''ħ'':
:: <math> |r × p| = m v r = n \hbar. </math>
:: <math>L = rm_\mathrm{e}v = n \hbar.</math>
<math display="block">L = rmv_\perp,</math>
: This quantum rule determines the electron's momentum (p) at any radius (r), for each integer n:
:: <math> p = m_\mathrm{e}v = \frac{n \hbar}{r}. </math>


* '''classical electromagnetism'''
* '''classical electromagnetism'''
: The electron is held in a circular orbit by electrostatic attraction. The centripetal force is equal to the Coulomb force.
: The electron is held in a circular orbit by electrostatic attraction. The centripetal force is therefore equal to the Coulomb force.
:: <math> \frac{m_\mathrm{e} v^2}{r} = \frac{Zk_\mathrm{e} e^2}{r^2},</math>
:: <math> \frac{m_\mathrm{e} v^2}{r} = \frac{Zk_\mathrm{e} e^2}{r^2},</math>
: where ''m''<sub>e</sub> is the electron's mass, ''e'' is the elementary charge, ''k''<sub>e</sub> is the Coulomb constant and ''Z'' is the atom's atomic number. It is assumed here that the mass of the nucleus is much larger than the electron mass (which is a good assumption). This equation determines the electron's momentum at any radius:
: where ''m''<sub>e</sub> is the electron's mass, ''e'' is the elementary charge, ''k''<sub>e</sub> is the Coulomb constant and ''Z'' is the atom's atomic number. It is assumed here that the mass of the nucleus is much larger than the electron mass (which is a good assumption). This classical equation determines the square of the electron's momentum (p) at any radius (r), for each integer n:
:: <math> (m_\mathrm{e} v)^2 = \frac{Zk_\mathrm{e} e^2}{r}. </math>
:: <math> p^2 = (m_\mathrm{e} v)^2 = m_\mathrm{e} \, \frac{Zk_\mathrm{e} e^2}{r}. </math>
: It also determines the electron's total energy at any radius:
 
:: <math> E = -\frac{1}{2} m_\mathrm{e} v^2.</math>
=Calculation of energy levels=
: The total energy is negative and inversely proportional to ''r''. This means that it takes energy to pull the orbiting electron away from the proton. For infinite values of ''r'', the energy is zero, corresponding to a motionless electron infinitely far from the proton.
Classical energy is the sum of kinetic and potential energy. Classical kinetic energy is equal to one half of the mass multiplied by the velocity squared.  And from the previous section, the momentum squared turns out to be equal to the Coulomb potential multiplied by the electron mass.
:: <math> E = K + P = \frac{m_\mathrm{e} v^2}{2} - \frac{Zk_\mathrm{e} e^2}{r} = \frac{p^2}{2 m_\mathrm{e}} - \frac{p^2}{m_\mathrm{e}} = -\frac{p^2}{2 m_\mathrm{e}} </math>
: The total energy here is negative and inversely proportional to ''r''. This means that it takes energy to pull the orbiting electron away from the atom. For infinite values of ''r'', the energy is zero, corresponding to a motionless electron infinitely far from the proton. It will be advantageous to represent the Coulomb constant ''k''<sub>e</sub> in terms of the Reduced Planck constant ''ħ'', the speed of light ''c'', the elementary charge ''e'', and the fine-structure constant ''α''.
:: <math>k_\mathrm{e} = \frac{1}{4\pi\varepsilon_0} = \frac
{\alpha \hbar c}{e^2}</math>
: From whence Bohr's three equations become:
:: <math> p = \frac{n \hbar}{r}. </math>
:: <math> p^2 = m_\mathrm{e} \, \frac{Z \alpha \hbar c}{r}. </math>
:: <math> E = -\frac{p^2}{2 m_\mathrm{e}} </math>


=Conversion to Bully Metric Units=
=Conversion to Bully Metric Units=
===The Quantization Rule===
[[File:Bully Metric Quantization of Angular Momentum.png|thumb|450px|Quantization of angular momentum demands an integer value for the product of orbital radius with the momentum perpendicular to the radius.  This appears as a series of parallel straight lines on a log-log plot.  The above graphic includes plots for principle quantum numbers one through ten (n = 1 .. 10), and for various powers of ten (n = 100, 1000, 10000, and 100000).]]
Bohr's quantization rule:
:: <math> p = \frac{n \hbar}{r}. </math>


In Bully Metric units, the speed of light (c = 1 la / ta),  the reduced Planck constant (ħ = 1 An), and the elementary charge (e) are all normalized, which means that many of the electron's properties carry the same numeric value:
Can be written in Bully units as:
:: <math> p = \frac{n}{r} \, An</math>
This rule is not a special property of the Bohr atom, but rather, is a universal property of quantum mechanics called quantization of angular momentum. This rule has an extremely simple form when momentum and radius are plotted on a log-log graph using Bully units.  The quantization of angular momentum appears as a series of parallel straight lines with a slope of negative one, each line representing an integer value of the principle quantum number n. The lowest energy level (n = 1) has the property that the momentum is always equal to the numerical inverse of the radius.  For example, if an electron were to orbit a nucleus at 1 micropan (0.000001 la), then the quantization of angular momentum would require the electron's perpendicular momentum to be 1 actionat per micropan, or in other words a million actionats per length apan (1000000 An / la).  The slope of negative one indicates that momentum is proportional to the inverse of the radius.
 
===Bully Classical Electromagnetism===
In Bully Metric units, the speed of light (c = 1.0 la / ta),  the reduced Planck constant (ħ = 1.0 An), and the elementary charge (1.0 e) are all normalized, which means that many of the electron's properties carry the same numeric value but with differing units as shown in Table 1.


{| class="wikitable"
{| class="wikitable"
|+Table 1: Electron Properties
|+Table 1: Electron Properties
|-
|-
! colspan="2"|'''''Electron Mass'''''
! colspan="2"|'''''Electron Mass (m)'''''
! colspan="2"|'''''Rest Energy (mc<sup>2</sup>)'''''
! colspan="2"|'''''Rest Energy (mc<sup>2</sup>)'''''
! colspan="2"|'''''Angular Frequency (<math>\frac{mc^2}{\hbar}</math>)'''''
! colspan="2"|'''''(mcħ)'''''
|-
|-
| style="border-right:none;"|{{val|23717311.411}}
| style="border-right:none;"|{{val|23717311.411}}
| style="border-left :none;"| An ta / la<sup>2</sup>
| style="border-left :none;"| An ta la<sup>-2</sup>
| style="border-right:none;"|{{val|23717311.411}}
| style="border-right:none;"|{{val|23717311.411}}
| style="border-left :none;"| An / ta
| style="border-left :none;"| An ta<sup>-1</sup>
| style="border-right:none;"|{{val|23717311.411}}
| style="border-right:none;"|{{val|23717311.411}}
| style="border-left :none;"| ta<sup>-1</sup>
| style="border-left :none;"| An^2 la<sup>-1</sup>
|}
|}
===Bully Quantum Rule===
[[File:Bully Metric Bohr Model Hydrogen Atom.png|thumb|450px|Bohr's model of the hydrogen atom on a log-log plot in the Bully Metric units.  The black line represents allowed radius-momentum value combinations according to Bohr's classical electromagnetism equations.  The other lines represents allowed radius-momentum value combinations according to quantization of angular momentum.]]
Bohr's quantum rule:
:: <math> m_\mathrm{e} v r = n \hbar.</math>


Can be written in Bully Units as:
Bohr's classical electromagnetism equations:
:: <math> v r = \frac{n}{23717311.411} \, \frac{la^2}{ta} </math>
:: <math> p^2 = m_\mathrm{e} \, \frac{Z \alpha \hbar c}{r}. </math>
:: <math> E = -\frac{p^2}{2 m_\mathrm{e}} </math>
Can be written in Bully units as shown below (note that 137.035999177 is the inverse fine-structure constant):
:: <math> p^2 = \frac{Z}{r} \frac{23717311.411}{137.035999177} \frac{An^2}{la}.</math>
:: <math> E =  -\frac{Z}{r} \frac{1}{2 \times 137.035999177} \frac{An\,la}{ta}.</math>
For a hydrogen atom with one proton (Z = 1), this becomes:
:: <math> p^2 = \frac{1}{r} \frac{23717311.411}{137.035999177} \frac{An^2}{la}.</math>
:: <math> E =  -\frac{1}{r} \frac{1}{2 \times 137.035999177} \frac{An\,la}{ta}.</math>
<br/>
When momentum and radius are plotted on a log-log graph using Bully units, Bohr's classical electromagnetism momentum equation appears as a straight line with a slope of negative two (negative two indicating that momentum squared is proportional to the inverse of the radius).


===Bully Classical Electromagnetism===
===Bully Metric Solutions for Bohr's Hydrogen Atom===
Bohr's classical velocity equation:
:: <math> p = \frac{n}{r} \, An</math>
:: <math> v^2 = \frac{Zk_\mathrm{e} e^2}{m_\mathrm{e} r}. </math>
:: <math> p^2 = \frac{1}{r} \frac{23717311.411}{137.035999177} \frac{An^2}{la}.</math>
:: <math> E =  -\frac{1}{r} \frac{1}{2 \times 137.035999177} \frac{An\,la}{ta}.</math>


Can be written in Bully Units as:
* '''The solution'''
:: <math> v^2 r = \frac{Zk_\mathrm{e} e^2}{23717311.411 \frac{An \, ta}{la^2}}. </math>
:The above two equations are sufficient to find exact r and p values (two equations in two unknowns) for each given integer n.  Dividing momentum squared by momentum, the radius dependence drops out:
 
:: <math> p = \frac{p^2}{p} = \frac{1}{n} \frac{23717311.411}{137.035999177} \frac{An}{la}.</math>
It will be advantageous to represent the Coulomb constant ''k''<sub>e</sub> in terms of the Reduced Planck constant ''ħ'', the speed of light ''c'', the elementary charge ''e'', and the fine-structure constant ''α''.
:: <math> v = \frac{-2E}{p} = -\frac{1}{n} \frac{1}{137.035999177} \frac{la}{ta}.</math>
 
:: <math>k_\mathrm{e} = \frac{1}{4\pi\varepsilon_0} = \frac
{\alpha \hbar c}{e^2}</math>
 
From whence:
:: <math> v^2 r = \frac{Z {\alpha}}{23717311.411} \frac{la^3}{ta^2}. </math>
 
Substituting in the value for the inverse fine-structure constant:
:: <math> v^2 r = \frac{Z}{23717311.411 \times {137.035999177}} \frac{la^3}{ta^2}. </math>
 
=Bully Bohr Atom=
Bohr's two equations written in Bully Metric format are:
:: <math> |v| r = \frac{n}{23717311.411} \, \frac{la^2}{ta} </math>
:: <math> v^2 r = \frac{Z}{23717311.411 \times {137.035999177}} \frac{la^3}{ta^2}. </math>
Where ''r'' is the radius of the Bohr orbital, ''v'' is the electron velocity as it orbits the nucleus, ''n'' is the principal quantum number and ''Z'' is the atom's atomic number.  From these two equations, one can determine the radius (r), velocity (v), and energy (E) of each of the Bohr electron orbits.
 
:: <math> r = \frac{(v r)^2}{v^2 r} = \frac{137.035999177}{Z} \, \frac{n^2}{23717311.411} la. </math>
 
:: <math> |v| = \frac{v^2 r}{|v| r} = \frac{Z}{137.035999177} \, \frac{1}{n} \, \frac{la}{ta}. </math>
 
:: <math> E  = \frac{1}{2} m v^2 = \frac{(Z)^2}{(137.035999177)^2} \, \frac{23717311.411}{n^2} \, \frac{An}{ta}.</math>


See Table 2 for the list of Bohr hydrogen atom energy level solutions in Bully Metric units.  Table 3 provides a list of photons that are emitted or absorbed when an electron transitions to a different energy level within the Bohr hydrogen atom.


{| class="wikitable" style="padding: 0; text-align: center; width: 0; white-space: nowrap;"
{| class="wikitable" style="padding: 0; text-align: center; width: 0; white-space: nowrap;"
Line 113: Line 116:
|| 6 || 0.001216 ||  -17.541 || 28845.597 || 0.000208004
|| 6 || 0.001216 ||  -17.541 || 28845.597 || 0.000208004
|-
|-
|| 4 || 0.001824 ||  -39.468 || 43268.396 || 0.000092446
|| 5 || 0.001459 ||  -25.260 || 34614.717 || 0.000144447
|-
|-
|| 4 || 0.001824 ||  -39.468 || 43268.396 || 0.000092446
|| 4 || 0.001824 ||  -39.468 || 43268.396 || 0.000092446
Line 123: Line 126:
|| 1 || 0.007297 ||  -631.489 || 173073.583 || 0.000005778
|| 1 || 0.007297 ||  -631.489 || 173073.583 || 0.000005778
|}
|}
=== Table ===
=== Table ===
[[File:Hydrogen transitions.svg|thumb|right|400px|Electron transitions and their resulting wavelengths for hydrogen. Energy levels are not to scale.]]
{| class="wikitable" style="padding: 0; text-align: center; width: 0; white-space: nowrap;"
{| class="wikitable" style="padding: 0; text-align: center; width: 0; white-space: nowrap;"
|+Table 2: Bohr Model Energy Levels
|+Table 3: Photon
|-
|-
! Transition
! Transition
Line 135: Line 137:
! Brackett series <br/> (n=4)
! Brackett series <br/> (n=4)
|-
|-
| n→∞ || 631.152904 <br/>-631.489478 <br/>=0.336574 || 157.875323 <br/>-157.872370 <br/>=-0.002954 || 70.143290 <br/>-70.165498 <br/>=0.022207 || 39.468831 <br/>-39.468092 <br/>=-0.000738
| n→∞ || 631.152904 <br/>631.489478 <br/><span style="color:red" >0.336574</span> || 157.875323 <br/>157.872370 <br/><span style="color:red" >-0.002954</span> || 70.143290 <br/>70.165498 <br/><span style="color:red" >0.022207</span> || 39.468831 <br/>39.468092 <br/><span style="color:red" >-0.000738</span>
|-
|-
| n→9 || 623.360648 <br/>-623.693312 <br/>=0.332664 || 150.038067 <br/>-150.076203 <br/>=0.038136 || 62.346214 <br/>-62.369331 <br/>=0.023117 || 31.670641 <br/>-31.671926 <br/>=0.001285
| n→9 || 623.360648 <br/>623.693312 <br/><span style="color:red" >0.332664</span> || 150.038067 <br/>150.076203 <br/><span style="color:red" >0.038136</span> || 62.346214 <br/>62.369331 <br/><span style="color:red" >0.023117</span> || 31.670641 <br/>31.671926 <br/><span style="color:red" >0.001285</span>
|-
|-
| n→8 || 621.290915 <br/>-621.622455 <br/>=0.331540 || 147.967622 <br/>-148.005346 <br/>=0.037724 || 60.282375 <br/>-60.298474 <br/>=0.016099 || 29.601623 <br/>-29.601069 <br/>=-0.000554
| n→8 || 621.290915 <br/>621.622455 <br/><span style="color:red" >0.331540</span> || 147.967622 <br/>148.005346 <br/><span style="color:red" >0.037724</span> || 60.282375 <br/>60.298474 <br/><span style="color:red" >0.016099</span> || 29.601623 <br/>29.601069 <br/><span style="color:red" >-0.000554</span>
|-
|-
| n→7 || 618.272041 <br/>-618.601938 <br/>=0.329896 || 144.948283 <br/>-144.984829 <br/>=0.036546 || 57.259259 <br/>-57.277957 <br/>=0.018698 || 26.567662 <br/>-26.580552 <br/>=0.012890
| n→7 || 618.272041 <br/>618.601938 <br/><span style="color:red" >0.329896</span> || 144.948283 <br/>144.984829 <br/><span style="color:red" >0.036546</span> || 57.259259 <br/>57.277957 <br/><span style="color:red" >0.018698</span> || 26.567662 <br/>26.580552 <br/><span style="color:red" >0.012890</span>
|-
|-
| n→6 || 613.620732 <br/>-613.948104 <br/>=0.327372 || 140.295678 <br/>-140.330995 <br/>=0.035317 || 52.601056 <br/>-52.624123 <br/>=0.023067 || 21.922116 <br/>-21.926718 <br/>=0.004602
| n→6 || 613.620732 <br/>613.948104 <br/><span style="color:red" >0.327372</span> || 140.295678 <br/>140.330995 <br/><span style="color:red" >0.035317</span> || 52.601056 <br/>52.624123 <br/><span style="color:red" >0.023067</span> || 21.922116 <br/>21.926718 <br/><span style="color:red" >0.004602</span>
|-
|-
| n→5 || 605.906685 <br/>-606.229899 <br/>=0.323214 || 132.579027 <br/>-132.612790 <br/>=0.033764 || 44.887329 <br/>-44.905918 <br/>=0.018590 || 14.205272 <br/>-14.208513 <br/>=0.003242
| n→5 || 605.906685 <br/>606.229899 <br/><span style="color:red" >0.323214</span> || 132.579027 <br/>132.612790 <br/><span style="color:red" >0.033764</span> || 44.887329 <br/>44.905918 <br/><span style="color:red" >0.018590</span> || 14.205272 <br/>14.208513 <br/><span style="color:red" >0.003242</span>
|-
|-
| n→4 || 591.705868 <br/>-592.021386 <br/>=0.315518 || 118.373611 <br/>-118.404277 <br/>=0.030666 || 30.690963 <br/>-30.697405 <br/>=0.006442 ||  
| n→4 || 591.705868 <br/>592.021386 <br/><span style="color:red" >0.315518</span> || 118.373611 <br/>118.404277 <br/><span style="color:red" >0.030666</span> || 30.690963 <br/>30.697405 <br/><span style="color:red" >0.006442</span> ||  
|-
|-
| n→3 || 561.025966 <br/>-561.323981 <br/>=0.298015 || 87.684591 <br/>-87.706872 <br/>=0.022281 ||  ||  
| n→3 || 561.024872 <br/>561.323981 <br/><span style="color:red" >0.299109</span> || 87.684591 <br/>87.706872 <br/><span style="color:red" >0.022281</span> ||  ||  
|-
|-
| n→2 || 473.364938 <br/>-473.617109 <br/>=0.252171 ||  ||  ||  
| n→2 || 473.364899 <br/>473.617109 <br/><span style="color:red" >0.252210</span> ||  ||  ||  
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[[File:Bully Metric values of Hydrogen transitions.png|Electron shell transitions of Hydrogen atom with energies listed in Bully Metric values]]

Latest revision as of 21:40, 29 October 2024

The following text was copied from the Wikipedia article about the Bohr model and was adapted to use Bully Metric Units:

File:Bohr atom model.svg
The Bohr model of the hydrogen atom (Template:Nowrap) or a hydrogen-like ion (Template:Nowrap), where the negatively charged electron confined to an atomic shell encircles a small, positively charged atomic nucleus and where an electron jumps between orbits, is accompanied by an emitted or absorbed amount of electromagnetic energy ().[1] The orbits in which the electron may travel are shown as grey circles; their radius increases as n2, where n is the principal quantum number. The Template:Nowrap transition depicted here produces the first line of the Balmer series, and for hydrogen (Template:Nowrap) it results in a photon of wavelength 71 millapan (656 nanometer red light).

In atomic physics, the Bohr model or Rutherford–Bohr model was the first successful model of the atom. Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's nuclear model. It supplanted the plum pudding model of J J Thomson only to be replaced by the quantum atomic model in the 1920s. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogous to the structure of the Solar System, but with attraction provided by electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values).

Development

In 1913 Niels Bohr put forth three postulates to provide an electron model consistent with Rutherford's nuclear model:

  1. The electron is able to revolve in certain stable orbits around the nucleus without radiating any energy, contrary to what classical electromagnetism suggests. These stable orbits are called stationary orbits and are attained at certain discrete distances from the nucleus. The electron cannot have any other orbit in between the discrete ones.
  2. The stationary orbits are attained at distances for which the angular momentum of the revolving electron is an integer multiple of the reduced Planck constant: , where is called the principal quantum number, and . The lowest value of is 1; this gives the smallest possible orbital radius, known as the Bohr radius, of 5.777 889 micropan (52.917 721 picometers) for hydrogen. Once an electron is in this lowest orbit, it can get no closer to the nucleus.
  3. Electrons can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency determined by the energy difference of the levels according to the Planck relation: , where is the Planck constant.

Calculation of the orbits

The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light. Calculation of the orbits requires two assumptions, a quantum rule and classical electromagnetism.

  • A quantum rule
The magnitude of angular momentum Template:Nowrap is an integer multiple of ħ:
This quantum rule determines the electron's momentum (p) at any radius (r), for each integer n:
  • classical electromagnetism
The electron is held in a circular orbit by electrostatic attraction. The centripetal force is therefore equal to the Coulomb force.
where me is the electron's mass, e is the elementary charge, ke is the Coulomb constant and Z is the atom's atomic number. It is assumed here that the mass of the nucleus is much larger than the electron mass (which is a good assumption). This classical equation determines the square of the electron's momentum (p) at any radius (r), for each integer n:

Calculation of energy levels

Classical energy is the sum of kinetic and potential energy. Classical kinetic energy is equal to one half of the mass multiplied by the velocity squared. And from the previous section, the momentum squared turns out to be equal to the Coulomb potential multiplied by the electron mass.

The total energy here is negative and inversely proportional to r. This means that it takes energy to pull the orbiting electron away from the atom. For infinite values of r, the energy is zero, corresponding to a motionless electron infinitely far from the proton. It will be advantageous to represent the Coulomb constant ke in terms of the Reduced Planck constant ħ, the speed of light c, the elementary charge e, and the fine-structure constant α.
From whence Bohr's three equations become:

Conversion to Bully Metric Units

The Quantization Rule

File:Bully Metric Quantization of Angular Momentum.png
Quantization of angular momentum demands an integer value for the product of orbital radius with the momentum perpendicular to the radius. This appears as a series of parallel straight lines on a log-log plot. The above graphic includes plots for principle quantum numbers one through ten (n = 1 .. 10), and for various powers of ten (n = 100, 1000, 10000, and 100000).

Bohr's quantization rule:

Can be written in Bully units as:

This rule is not a special property of the Bohr atom, but rather, is a universal property of quantum mechanics called quantization of angular momentum. This rule has an extremely simple form when momentum and radius are plotted on a log-log graph using Bully units. The quantization of angular momentum appears as a series of parallel straight lines with a slope of negative one, each line representing an integer value of the principle quantum number n. The lowest energy level (n = 1) has the property that the momentum is always equal to the numerical inverse of the radius. For example, if an electron were to orbit a nucleus at 1 micropan (0.000001 la), then the quantization of angular momentum would require the electron's perpendicular momentum to be 1 actionat per micropan, or in other words a million actionats per length apan (1000000 An / la). The slope of negative one indicates that momentum is proportional to the inverse of the radius.

Bully Classical Electromagnetism

In Bully Metric units, the speed of light (c = 1.0 la / ta), the reduced Planck constant (ħ = 1.0 An), and the elementary charge (1.0 e) are all normalized, which means that many of the electron's properties carry the same numeric value but with differing units as shown in Table 1.

Table 1: Electron Properties
Electron Mass (m) Rest Energy (mc2) (mcħ)
Template:Val An ta la-2 Template:Val An ta-1 Template:Val An^2 la-1
File:Bully Metric Bohr Model Hydrogen Atom.png
Bohr's model of the hydrogen atom on a log-log plot in the Bully Metric units. The black line represents allowed radius-momentum value combinations according to Bohr's classical electromagnetism equations. The other lines represents allowed radius-momentum value combinations according to quantization of angular momentum.

Bohr's classical electromagnetism equations:

Can be written in Bully units as shown below (note that 137.035999177 is the inverse fine-structure constant):

For a hydrogen atom with one proton (Z = 1), this becomes:


When momentum and radius are plotted on a log-log graph using Bully units, Bohr's classical electromagnetism momentum equation appears as a straight line with a slope of negative two (negative two indicating that momentum squared is proportional to the inverse of the radius).

Bully Metric Solutions for Bohr's Hydrogen Atom

  • The solution
The above two equations are sufficient to find exact r and p values (two equations in two unknowns) for each given integer n. Dividing momentum squared by momentum, the radius dependence drops out:

See Table 2 for the list of Bohr hydrogen atom energy level solutions in Bully Metric units. Table 3 provides a list of photons that are emitted or absorbed when an electron transitions to a different energy level within the Bohr hydrogen atom.

Table 2: Bohr Model Hydrogen Energy Levels
n Velocity Energy Momentum Radius
0.000000 0.000 0.000
1000 0.000007 -0.001 173.074 5.777889273
100 0.000073 -0.063 1730.736 0.057778893
10 0.000730 -6.315 17307.358 0.000577789
9 0.000811 -7.796 19230.398 0.000468009
8 0.000912 -9.867 21634.198 0.000369785
7 0.001042 -12.888 24724.798 0.000283117
6 0.001216 -17.541 28845.597 0.000208004
5 0.001459 -25.260 34614.717 0.000144447
4 0.001824 -39.468 43268.396 0.000092446
3 0.002432 -70.165 57691.194 0.000052001
2 0.003649 -157.872 86536.792 0.000023112
1 0.007297 -631.489 173073.583 0.000005778

Table

Table 3: Photon
Transition Lyman series
(n=1)
Balmer series
(n=2)
Paschen series
(n=3)
Brackett series
(n=4)
n→∞ 631.152904
631.489478
0.336574
157.875323
157.872370
-0.002954
70.143290
70.165498
0.022207
39.468831
39.468092
-0.000738
n→9 623.360648
623.693312
0.332664
150.038067
150.076203
0.038136
62.346214
62.369331
0.023117
31.670641
31.671926
0.001285
n→8 621.290915
621.622455
0.331540
147.967622
148.005346
0.037724
60.282375
60.298474
0.016099
29.601623
29.601069
-0.000554
n→7 618.272041
618.601938
0.329896
144.948283
144.984829
0.036546
57.259259
57.277957
0.018698
26.567662
26.580552
0.012890
n→6 613.620732
613.948104
0.327372
140.295678
140.330995
0.035317
52.601056
52.624123
0.023067
21.922116
21.926718
0.004602
n→5 605.906685
606.229899
0.323214
132.579027
132.612790
0.033764
44.887329
44.905918
0.018590
14.205272
14.208513
0.003242
n→4 591.705868
592.021386
0.315518
118.373611
118.404277
0.030666
30.690963
30.697405
0.006442
n→3 561.024872
561.323981
0.299109
87.684591
87.706872
0.022281
n→2 473.364899
473.617109
0.252210

Electron shell transitions of Hydrogen atom with energies listed in Bully Metric values