Examples and Exercises Normalizing a Wavefunction Find a normalizing factor of the hydrogen’s electron wavefunction Ne d N e * 2 2 r / a0 0 N 2 r / a0 Function of r, using spherical coordinate r dr sin d 2 0 2 r e 2 r / a0 2 d 1 0 dr 2 2 x 0 N 2 a 3 0 2 2 1 0 4 1 N 3 a 0 1/ 2 1 3 a0 1/ 2 e r / a0 n e ax n! dx a n 1 Eigen eqaution Operator Constant Function Show if eax is an eigenfunction of the operator d/dx de ax ae ax dx Show if 2 ax e is an eigenfunction of the operator d/dx de ax dx 2 2 axe ax 2 Orthogonal wavefunction d 0 j * i Both sinx and sin2x are eigenfunction of d/dx, show if sinx and sin2x are orthogonal. sin ax sin bx dx 2 0 sin x sin 2 xdx sin( a b ) x 2(a b) sin( 1 2 ) x 2 (1 2 ) sin( a b ) x 2(a b) sin( 1 2 ) x 2 (1 2 ) C C 0 Expectation Value X X j d * i Calculate the average value of the distance of an e- from the n of H-atom H e 1 3 a 0 r r j d * i 0 n x e ax n! dx a n 1 1/ 2 1 a 3 0 e r / a0 3 r e 0 2 r / a0 dr sin d 0 4 1 3! a 0 a 3 0 2 4 2 2 2 d 0 3 2 a 0 79 . 4 pm Uncertainty Principle Uncertainty in position along an axis Uncenrtianty in linear momentum pq 1 2 Calculate the minimum uncertainty in the position of mass 1.0 g and the speed is known within 1 mm s-1. q 2p 2mv 1 . 055 10 2 1 . 0 10 5 10 26 m 3 34 Js kg 1 10 6 ms 1 Probability (Particle in a box) Wave function of conjugated electron of polyene can be approximated by PAB. Find the probability of locating electron between x=0 and x=0.2 nm in the lowest state in conjugated molecule of length 1.0 nm l 0 2 n dx 2 L l sin 2 L 0 . 05 dx L 0 1 nx 1 2n sin 2 nl L when n=1 L=1.0 nm and l = 0.2 nm Harmonic Oscillator x N H y e 2 y /2 y mk 2 x 1/ 4 Find the normalizing factor of Harmonic Oscillator wavefunction dx dy N * * 2 N 2 N 1/ 2 H ' H 'e 2 ! y 2 dy H y e y 2 ! 1 1 2 1/ 2 N 1 1/ 2 2 ! 0 1/ 2 2 ! if ' if ' 1/ 2 2 dy Harmonic Oscillator x N H y e y mk 2 x 2 y /2 1/ 4 The bending motion of CO2 molecule can be considered as a harmonic oscillator, find the mean displacement of the oscillator x x dx N * 2 2 H e N 2 2 y /2 2 xH e H yH e y y /2 dy 2 dy yH H 1 H 1 H yH ' e y 2 dy 0 H 1 H e y 2 dy 1 2 H 1 H e y 2 dy Exercises Calculate the speed of an electron of wavelength 3.0 cm Calculate the Brogile wavelength of a mass of 1.0 g travelling at 1.0 cm s-1 Calculate the probability of a particle in ground state between x=4.0 and 5.0 cm in a box of 10.0 cm length Calculate the probability of a hydrogen’s electron in ground state to be found within radius a0/2 from the nucleus Exercises Identifiy which functions are eigenfunctions of the operator d/dx eikx coskx e-ax 3 Calculate the energy separation between the levels n=2 and n=6 of an electron in a box of length 1.0 nm What are the most likely locations of a particle in a box of length L in the state n=3? Exercises What are the most likely locations of a particle in a harmonic oscillator well of lin the state =5 ? Confirm that the wavefunction for the ground state of a one- dimention linear harmonic oscillator is a solution of the Schrödinger eqaution Write down the Harmonic Oscillator wavefunction in the state =0 and 4 Write down the Rigid Roter wavefunction Y0,0 , Y1,2 , Y2,1 and Y2,-2 and calculate their energies