Physics 2D Lecture Slides UCSD Physics Vivek Sharma Dec 1 QM in - - PowerPoint PPT Presentation

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Physics 2D Lecture Slides UCSD Physics Vivek Sharma Dec 1 QM in - - PowerPoint PPT Presentation

Physics 2D Lecture Slides UCSD Physics Vivek Sharma Dec 1 QM in 3 Dimensions Learn to extend S. Eq and its solutions from toy examples in 1-Dimension (x) three orthogonal dimensions (r x,y,z) = + + r


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SLIDE 1
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SLIDE 2

Physics 2D Lecture Slides Dec 1

Vivek Sharma UCSD Physics

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SLIDE 3

QM in 3 Dimensions

  • Learn to extend S. Eq and its

solutions from “toy” examples in 1-Dimension (x) → three

  • rthogonal dimensions

(r ≡x,y,z)

  • Then transform the systems

– Particle in 1D rigid box 3D rigid box – 1D Harmonic Oscillator 3D Harmonic Oscillator

  • Keep an eye on the number
  • f different integers needed

to specify system 1 3 (corresponding to 3 available degrees of freedom x,y,z)

y z x

ˆ ˆ ˆ r ix jy kz = + +

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SLIDE 4

Quantum Mechanics In 3D: Particle in 3D Box

Extension of a Particle In a Box with rigid walls 1D → 3D ⇒ Box with Rigid Walls (U=∞) in X,Y,Z dimensions

y y=0 y=L z=L z

Ask same questions:

  • Location of particle in 3d Box
  • Momentum
  • Kinetic Energy, Total Energy
  • Expectation values in 3D

To find the Wavefunction and various expectation values, we must first set up the appropriate TDSE & TISE

U(r)=0 for (0<x,y,z,<L)

x

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SLIDE 5

The Schrodinger Equation in 3 Dimensions: Cartesian Coordinates

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

Time Dependent Schrodinger Eqn: ( , , , ) ( , , , ) ( , , ) ( , ) .....In 3D 2 2 2 2 2 x y z t x y x y z t U x y z x t i m t m x m y m z m So ∂ ∂ ∂ ∇ ∂Ψ − ∇ Ψ + Ψ = ∂ − ∇ = + ⎛ ⎞ ⎛ ⎞ ∂ ∂ ∂ − − + − ⎜ ⎟ ⎜ ⎟ ∂ ∂ ∂ ⎝ ⎠ ⎝ +∂ ⎠ = + ∂ ∂

  • x

2 x x

[K ] + [K ] + [K ] [ ] ( , ) [ ] ( , ) is still the Energy Conservation Eq Stationary states are those for which all proba [ ] = bilities so H x t E K x t z ⎛ ⎞= Ψ ⎟ ⎠ = ⎜ ⎝ Ψ

  • i t

are and are given by the solution of the TDSE in seperable form: = (r)e This statement is simply an ext constant in time ( ension of what we , derive , , ) ( , ) d in case of x y z t r t

ω

ψ Ψ =Ψ

  • 1D

time-independent potential

y z x

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SLIDE 6

Particle in 3D Rigid Box : Separation of Orthogonal Spatial (x,y,z) Variables

1 2 3 1 2 2 3 2

in 3D: x,y,z independent of each ( , , ) ( ) ( ) ( ) and substitute in the master TISE, after dividing thruout by = ( ) ( ) (

  • ( , , )

( ,

  • ther , wr

, ) ( , , ) and ) ( , ite , ) n 2m x y z TISE x y z U x y z x y z E x y x y z x y z z ψ ψ ψ ψ ψ ψ ψ ψ ψ ψ ψ ∇ = + =

  • 2

2 1 2 1 2 2 2 2 2 2 3 2 3 2 1 2 2

( ) 1 2 ( ) This can only be true if each term is c

  • ting that U(r)=0 fo
  • nstant for all x,y,z

( ) 1 2 ( ) ( 2 r (0<x,y,z,<L) ( ) 1 2 ( ) z E Const m z z y m x m x x x m y y ψ ψ ψ ψ ψ ψ ψ ⎛ ⎞ ∂ − + ⎜ ⎟ ⎛ ⎞ ∂ + − = ⇒ ⎛ ⎞ ∂ − ⎜ ⎟ ∂ ⎝ ⎠ ∂ ⎝ ⎠ = ⇒ − ⎜ ⎟ ⎝ ⎠ ∂ ∂

  • 2

2 3 3 3 2 2 2 2 2 2 1 1 2 2 1 2 3

) ( ) ; (Total Energy of 3D system) Each term looks like ( ) ( ) ; 2 With E particle in E E E=Constan 1D box (just a different dimension) ( ) ( ) 2 So wavefunctions t z E z m z y y E x E x y m ψ ψ ψ ψ ψ ∂ − = ∂ − ∂ = = = ∂ + + ∂

  • 3

3 1 2 2 1

must be like , ( ) sin x , ( ) s ) s n in ( i y y k x k z k z ψ ψ ψ ∝ ∝ ∝

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SLIDE 7

Particle in 3D Rigid Box : Separation of Orthogonal Variables

1 1 2 2 3 3 i

Wavefunctions are like , ( ) sin Continuity Conditions for and its fi ( ) sin y Leads to usual Quantization of Linear Momentum p= k .....in 3D rst spatial derivative ( ) s sin x ,

x i i

z k z n k x L y k p k ψ ψ π ψ π ψ ∝ ∝ ⇒ = ∝ =

  • 1

2 3 2 2 1 3 1 2 2 2 2 2 2 3

; ; Note: by usual Uncertainty Principle argumen (n ,n ,n 1,2,3,.. ) t neither of n ,n ,n 0! ( ?) 1 Particle Energy E = K+U = K +0 = ) 2 ( m 2 (

z y x y z

n why p n L n mL p n L L p p p π π π ⎛ ⎞ ⎛ ⎞ = = ∞ ⎜ ⎟ ⎜ ⎛ ⎞ = ⎜ ⎟ ⎝ ⎠ ⎟ ⎝ ⎠ ⎝ = ⎠ + + =

  • 2

2 2 1 2 3 2 1 2 3 2 1 E i 3

  • 3

1

) Energy is again quantized and brought to you by integers (independent) and (r)=A sin (A = Overall Normalization Co sin y (r) nstant) (r,t)= e [ si n ,n ,n sin x sin x ys n in ]

t

k n n k A k k k k z z ψ ψ + + = Ψ

  • E
  • i

e

t

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SLIDE 8

Particle in 3D Box :Wave function Normalization Condition

3 * 1 1 2 1 x,y, E E

  • i
  • i

2 E E i i * 2 2 2 2 2 3 * 3 z 2

(r) e [ sin y e (r) e [ s (r,t)= sin ] (r,t)= sin ] (r,t) sin x sin x sin x in y e [ si Normalization Co (r,t)= sin ] ndition : 1 = P(r)dx n y dyd 1 z

t t t t

k z k k k A k A k A k z k k A z ψ ψ Ψ Ψ Ψ ⇒ Ψ = = =

∫∫∫

  • L

L L 2 3 3 E 2 2 2 1 2 3 x=0 y= 2 2

  • 1

z 3 i 2 =0

sin x dx s sin y dy sin z dz = ( 2 2 2 2 2 an r,t)= d [ s sin i i e x y n ] n

t

L k L L A A k L k k k k z L ⎛ ⎞⎛ ⎞⎛ ⎞ ⎜ ⎟⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟⎜ ⎟ ⎝ ⎠⎝ ⎠⎝ ⎠ ⎡ ⎤ ⎡ ⎤ ⇒ = ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ ⎣ ⎦ Ψ

∫ ∫ ∫

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SLIDE 9

Particle in 3D Box : Energy Spectrum & Degeneracy

1 2 3

2 2 2 2 2 n ,n ,n 1 2 3 i 2 2 111 2 2 2 211 121 112 2 2

3 Ground State Energy E 2 6 Next level 3 Ex E ( ); n 1, 2,3... , 2 s cited states E = E E 2 configurations of (r)= (x,y,z) have Different ame energy d

i

mL mL n n n n mL π π ψ ψ π = + + = ∞ ≠ = ⇒ = = ⇒

  • egeneracy

y y=L z=L z x x=L

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SLIDE 10

2 2 211 121 112 2

Degenerate States 6 E = E E 2mL π = =

  • x

y z E211 E121 E112 ψ E111 x y z ψ Ground State

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SLIDE 11

Probability Density Functions for Particle in 3D Box

Same Energy Degenerate States Cant tell by measuring energy if particle is in 211, 121, 112 quantum State

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SLIDE 12

Source of Degeneracy: How to “Lift” Degeneracy

  • Degeneracy came from the

threefold symmetry of a CUBICAL Box (Lx= Ly= Lz=L)

  • To Lift (remove) degeneracy

change each dimension such that CUBICAL box Rectangular Box

  • (Lx≠ Ly ≠ Lz)
  • Then

2 2 2 2 2 2 3 1 2 2 2 2

2 2 2

x y z

n n n E mL mL mL π π π ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ = + + ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠

Energy

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SLIDE 13

The Hydrogen Atom In Its Full Quantum Mechanical Glory

2 2 2

By example of particle in 3D box, need to use seperation of variables(x,y,z) to derive 3 in 1 1 This approach will dependent d ( ) M iffer

  • re compli
  • ential. eq

cated form of U than bo get x ns. U r r x y z ∝ = ⇒ + +

2 2 2 2

To simplify the situation, use appropriate variables Independent Cartesian (x,y,z)

  • Inde. Spherical Polar (r, ,

very ugly since we have a "conjoined triplet" Instead of writing Laplacian ) x y θ φ ∂ ∂ ∇ = + ∂ ∂ →

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

, write 1 sin TISE for (x,y,z)= (r, , ) become 1 r 1 (r, , ) (r, , ) r s 1 2m + 1 = s (E-U(r)) in si si n 1 sin s (r, , ) n in r r r r z r r r r r r θ θ θ θ θ θ θ θ φ ψ ψ θ ψ θ φ ψ θ φ ψ θ φ θ φ θ φ ∂ ∂ ⎛ ⎞ ⎜ ⎟ ∂ ∂ ⎝ ⎠ ∂ ∂ ⎛ ∂ ∂ ⎛ ⎞ ⎜ ⎟ ∂ ∂ ∂ + ∂ ∂ ∂ ∂ ∂ ⎞ ∇ + + ⎜ ⎟ ∂ ∂ ⎝ ⎠ ∂ ∂ ⎛ ⎞ + + ⎜ ∂ ⎠ ⎝ ⎟ ∂ ⎝ ⎠

  • !!!! fun!!!

(r, , ) =0 ψ θ φ

r

2

( ) kZe U r r =

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SLIDE 14

Spherical Polar Coordinate System

2

( sin ) Vol ( )( ) = r si ume Element dV n dV r d rd dr drd d θ φ θ θ θ φ =

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SLIDE 15

Don’t Panic: Its simpler than you think !

2 2 2 2 2 2 2 2 2 2 2 2

1 2m + (E-U(r)) sin Try to free up las 1 (r, , ) =0 r all except This requires multi t term fro plying thruout by sin si 1 sin si si si m n n n r r r r r r r r r ψ ψ ψ ψ θ φ φ θ ψ θ θ θ θ θ θ θ θ φ ∂ ∂ ⎛ ⎞ ⎜ ⎟ ∂ ∂ ⎝ ⎠ ⇒ ∂ ∂ ⎛ ⎞ ⎜ ⎟ ∂ ∂ ⎝ ⎠ ∂ ∂ ⎛ ⎞ + + ⎜ ⎟ ∂ ∂ ⎝ ⎠ ∂ + ∂ ∂ ∂

  • 2

2 2 2 2 2

2m ke + (E+ ) r (r, , )=R(r). ( ). ( ) Plug it into the TISE above & divide thruout by (r, , )=R(r). ( ). sin =0 For Seperation of Variables, W rite ( , , ) r Note tha ( t : ) n r r φ ψ θ φ θ φ ψ ψ θ ψ ψ θ φ φ θ θ θ φ θ ∂ ⎛ ⎞ + ⎜ ⎟ ∂ ⎝ ⎠ ∂ ∂ ∂ Θ Ψ Θ Φ Φ ∂

  • 2

2 2 2 2 2 2 2

( ). ( ) ( , , ) ( ) ( ) ( , , ) ( ) ( ) s R(r) r ( ) when substituted in TI in sin =0 Rearrange by ta sin king the sin SE ( ) 1 2m ke + (E+ ) r r R r r R r R r r R r r θ φ θ φ φ θ θ φ θ θ θ θ φ φ θ θ φ θ θ θ θ = Θ Φ ∂Ψ = Φ ∂ ∂Ψ = Θ ∂ ∂ ∂ ⎛ ∂ ∂Θ ⎛ ⎞ + + ⎜ ⎟ Θ ⎞ ⎜ ∂ ∂ ⎝ ⎟ ∂ ∂ ∂ ∂ ∂Θ ⇒ ∂ ∂Φ ∂ ∂ ∂ ⎝ Φ ⎠ ⎠ Φ

  • 2

2 2 2 2 2 2 2 2

2m ke 1 + (E+ ) r LHS is fn. of r, & RHS is fn of

  • nly , for equality to be true for all r,

, LHS= constant = RH term on RHS sin s S = sin sin m in =-

l

R r r R r r φ θ φ θ φ θ θ φ θ θ θ θ ∂ ∂ ⎛ ⎞ ⎜ ⎟ ∂ Φ Φ ∂ ⇒ ∂ ∂Θ ⎛ ⎞ + ⎜ ⎟ Θ ∂ ∂ ⎝ ⎝ ⎠ ⎠ ∂ ∂

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SLIDE 16

2 2 2 2 2 2 2 2 2

sin sin =m Divide Thruout by sin and arrange all terms with r aw Now go break up LHS to seperate the terms... r .. 2m ke LHS: + (E+ ) a & sin si y from r 1 n

l

R r r r r r R r R θ θ θ θ θ θ θ θ θ ∂ ∂Θ ⎛ ⎞ + ⎜ ⎟ Θ ∂ ∂ ⎝ ⎠ ∂ ∂ ⎛ ∂ ⎞ ∂ ∂ ⎜ ⎟ ∂ ∂ ⎝ ⎠ ⇒

  • 2

2 2 2 2

m 1 sin sin sin Same argument : LHS is fn of r, RHS is fn of , for them to be equal for a LHS = const = 2m ke (E+ )= r What do we have after shuffl ll r, = ( in 1) g RHS

l

l l R r r θ θ θ θ θ θ θ ∂ ∂Θ ⎛ ⎞ − ⎜ ⎟ ⎛ ⎞ + Θ ∂ ∂ ⎝ ⎠ ⇒ + ⎜ ⎟ ∂ ⎝ ⎠

  • 2

2 2 2 2 2 2 2 2 2 2

! m 1 sin ( 1) ( ) 0.....(2) sin sin ............... d ..(1) 1 2m ke ( 1) (E+ )- ( ) 0....( m 0. 3 . ) r T

l l

d R r l l r R r r dr d d l d d r l d r θ φ θ θ θ θ θ ⎡ ⎤ Θ ⎛ ⎞ + + − Θ ⎡ ⎤ ∂ + ⎛ ⎞ + = ⎜ ⎟ ⎢ ⎥ ∂ ⎝ ⎠ ⎣ ⎦ = ⎜ ⎟ ⎢ ⎥ ⎝ ⎠ ⎣ ⎦ Φ + Φ =

  • hese 3 "simple" diff. eqn describe the physics of the Hydrogen atom.

All we need to do now is guess the solutions of the diff. equations Each of them, clearly, has a different functional form

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SLIDE 17

Solutions of The S. Eq for Hydrogen Atom

2 2 2

d The Azimuthal Diff. Equation : m Solution : ( ) = A e but need to check "Good Wavefunction Condition" Wave Function must be Single Valued for all ( )= ( 2 ) ( ) = A e

l l

l im im

d

φ φ

φ φ φ φ φ π φ Φ + Φ = Φ ⇒ Φ Φ + ⇒ Φ

( 2 ) 2 2

A e 0, 1, 2, 3....( ) The Polar Diff. Eq: Solutions : go by the name of "Associated Legendre Functions" 1 m sin ( 1) ( ) sin si Quantum # n

l

l im l

d d Magnetic l d m l d

φ π

θ θ θ θ θ θ

+

⎡ ⎤ Θ ⎛ ⎞ + + − Θ = ⎜ ⎟ ⎢ ⎥ ⎝ ⎠ = ⎣ ⎦ ⇒ = ± ± ±

  • nly exist when the integers and

are related as follows 0, 1, 2, 3.... : Orbital Q ; ua p nt

  • sit

um N ive numb umber er 1 For 0, =0 ( ) = ; 2 For

l l l

l m l l l m l m θ = ± ± ± ± = = ⇒ Θ

2

1, =0, 1 Three Possibilities for the Orbital part of wavefunction 6 3 [ 1, 0] ( ) = cos [ 1, 1] ( ) = sin 2 2 10 [ 2, 0] ( ) = (3cos 1).... so on and so forth (see book) 4

l l l l

l m l m l m l m and θ θ θ θ θ θ = ± ⇒ = = ⇒ Θ = = ± ⇒ Θ = = ⇒ Θ −

Φ

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SLIDE 18

Solutions of The S. Eq for Hydrogen Atom

2 2 2 2 2 2 2 2

1 2m ke ( 1) The Radial Diff. Eqn: (E+ )- ( ) r : Associated Laguerre Functions R(r), Solutions exist only if:

  • 1. E>0 or has negtive values given by

ke 1 E=- 2a d R r l l r R r r dr r r Solutions n ⎡ ⎤ ∂ + ⎛ ⎞ + = ⎜ ⎟ ⎢ ⎥ ∂ ⎝ ⎠ ⎦ ⎝ ⎣ ⎛

  • 2

2

  • 2. And when n = integer such that

0,1,2,3,4,,,( 1) n = principal Quantum # or the "big daddy" qunatu To ; Bohr Summa m # : The hy Rad r droge ize n ius atom a l mke n = − ⎞ = = ⎜ ⎟ ⎠

  • n = 1,2,3,4,5,....

0,1,2,3,,4....( 1) m 0, 1, 2, 3,. Quantum # appear only in Trappe is brought to you d systems The Spati by the letters al Wave Function o f the Hydrogen Atom ..

l

l n l ∞ = − = ± ± ± ±

l

m

( , , ) ( ) . ( ) . ( ) Y (Spherical Harmonics)

l l

m nl lm nl l

r R r R θ φ θ φ Ψ = Θ Φ =

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SLIDE 19

Radial Wave Functions & Radial Prob Distributions

  • r/a

3/2 r

  • 2

a 3/2 2 3 2 3/2

R(r)= 2 e a 1 r (2 n 1 0 0 2 0 0 3 0 0

  • )e

a 2 2a 2 r (27 18 2 ) a 81 3a

l r a

r e a l m

− +

n=1 K shell n=2 L Shell n=3 M shell n=4 N Shell

…… l=0 s(harp) sub shell l=1 p(rincipal) sub shell l=2 d(iffuse) sub shell l=3 f(undamental) ss l=4 g sub shell ……..

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SLIDE 20

Symbolic Notation of Atomic States in Hydrogen

2 2 4 4 2 ( 0) ( 1) ( 2) ( 3) ( 4 3 3 3 ) ..... 1 4 3 1 s p s l p l d l f l g l s l s d n p s p = = = → = = ↓ 5 5 5 5 4 5 4 5 s p d f g d f

Note that:

  • n =1 non-degenerate system
  • n1>1 are all degenerate in l and ml.

All states have same energy But different spatial configuration

2 2

ke 1 E=- 2a n ⎛ ⎞ ⎜ ⎟ ⎝ ⎠

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SLIDE 21

Facts About Ground State of H Atom

  • r/a

3/2

  • r/a

100

2 1 1 ( ) e ; ( ) ; ( ) a 2 2 1 ( , , ) e ......look at it caref

  • 1. Spherically s

1, 0, ymmetric no , dependence (structure)

  • 2. Probab

ully i

l

n l r r a m R θ φ π θ φ π θ φ ⇒ = Θ = Φ = Ψ = ⇒ = = =

2 2 100 3

Likelihood of finding the electron is same at all , and depends only on the radial seperation (r) between elect 1 lity Per Unit Volume : ( , ron & the nucleus. 3 Energy ,

  • f Ground ta

) S

r a

r e a θ π θ φ φ

Ψ =

2

ke te =- 13.6 2a Overall The Ground state wavefunction of the hydrogen atom is quite Not much chemistry or Biology could develop if there was

  • nly the ground state of the Hydrogen Atom!

We nee boring eV = − d structure, we need variety, we need some curves!

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SLIDE 22

Interpreting Orbital Quantum Number (l)

2 RADIAL ORBITAL RADIAL ORBI 2 2 2 2 2 2 2 2 TAL 2 2

K 1 2m ke ( 1) Radial part of S.Eq K ;substitute this form for n: (E+ )- ( ) r For H Atom: E = E K K K + U = 1 2m ( 1)

  • 2m

d dR r l l r R r r dr dr r d dR l l r r dr dr r ke r ⎡ ⎤ + ⎛ ⎞+ = ⎜ ⎟ ⎢ ⎥ ⎝ ⎠ ⎣ ⎦ + ⎛ ⎞+ ⎜ + ⎟ − + ⎝ ⎠

  • [

]

ORBITAL RADIAL OR 2 2 2 2 B 2 2

( ) ( 1) Examine the equation, if we set get a diff. eq. in r 2m 1 2m ( ) 0 which Further, we also kno depends only on radi K K us w r of orb K tha i t t R r l l then r d dR r R r r dr dr ⎡ ⎤ = ⎢ ⎥ ⎣ ⎦ + ⎛ ⎞+ = ⎜ ⎟ ⎝ ⎠ =

  • 2

2 ITAL ORBIT

  • rb

2 AL 2 2 ORBITAL 2 2

L= r p ; |L| =mv r ( 1 1 ; K 2 2 Putting it all togather: K magnitude of ) | | ( 1) 2m Since integer=0,1,2,3...( A n-1) angular mome ng. 2 nt Mom

  • rbit

l l L l l r l L mv mr L posi mr tive × ⇒ + = = + = = = ⇒ = ⇒

  • um|

| ( 1) | | ( 1) : QUANTIZATION OF Electron's Angular Momentum L l l discrete values L l l = + = = +

  • p

r L

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SLIDE 23

Magnetic Quantum Number ml

(Right Hand Rule) QM: Can/Does L have a definite direction Classically, direction & Magnitud ? Proof by Negat ˆ Suppose L was precisely known/defined (L || z) e of L S always well defi n ed : n io L r p = ×

  • 2

z z z

Electron MUST be in x-y orbit plane z = 0 ; , in Hydrogen atom, L can not have precise measurable ince Uncertainty Principle & An p p ; !!! gular Momentum value : L 2 p z E L r p So m φ = × ⇒ ⇒ ∆ ∆ ∆ ⇒ ∆ ∞ ∆ ∞ ∆ =

∼ ∼

Z Z

The Z compo Arbitararily nent of L vector spins around Z axis (precesses). |L | ; 1, 2, 3... ( 1) It picking Z axis as a referen L :| L | ca | | (always) s n in ce directi c

  • :

e n

l l l

m Note L m l m l l < = = ± ± ± ± < +

  • Z

never be that |L | ( 1) (breaks Uncertainty Principle) So you see, the dance has begun !

l

m l l = = +

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SLIDE 24

L=2, ml=0,±1, ± 2 : Pictorially Sweeps Conical paths of different ϑ: Cos ϑ = LZ/L and average <LX> = 0 <LY> = 0

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SLIDE 25

What’s So “Magnetic” ?

Precessing electron Current in loop Magnetic Dipole moment µ More in this in Tomorrow’s lecture when we look at Energy States

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SLIDE 26

Radial Probability Densities

l

2 * 2 2 m 2

( , , ) ( ) . ( ) . ( ) ( , , ) | Y Probability Density Function in 3D: P(r, , ) = =| | Y | : 3D Volume element dV= r .sin . . .

  • Prob. of finding parti

| | . cle in a ti n

l l l

nl nl l m l n m m l l

Note d r R r r r d R d R θ φ θ φ θ θ φ φ φ θ θ Ψ = Θ Φ = Ψ Ψ Ψ =

l l

2 2 2 2 m 2 2 2 2 m

y volume dV is P.dV = | Y | .r .sin . . . The Radial part of Prob. distribution: P(r)dr P(r)dr= | ( ) | When | ( ) | ( ) & ( ) are auto-normalized then P(r)dr | | . | | = . |

l l l

lm l m m n nl n l l

R R r d R dr d d r d d

π π

θ θ φ φ φ θ φ θ θ Θ Θ Φ Φ

∫ ∫

2 2 2 2 nl 2 2

in other words Normalization Condition: 1 = r |R | dr Expectation Values P(r)=r | <f( | | . . ; r)>= f(r).P(r)dr

nl l

r r R d

∞ ∞

∫ ∫

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SLIDE 27

Ground State: Radial Probability Density

2 2 2 2 3 2 2 3 2 2

( ) | ( ) | .4 4 ( ) Probability of finding Electron for r>a To solve, employ change of variable 2r Define z= ; limits of integra 4 1 2 tion a

r a r a a r a r a

r e dr P r dr r r dr P r dr r e a change P a P z ψ π

− ∞ > ∞ > −

= ⇒ = ⎡ ⎤ ⎢ ⎥ = = ⎣ ⎦

2 2 2

(such integrals called Error. Fn) 1 66.7% =- [ 2 2] | 5 0.667 2 !!

z z

e z e z e d z

− − ∞

+ + = = ⇒