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{
"metadata": {
"name": "",
"signature": "sha256:177e44357417b2cfb0b476ada5b36a934225ade51d50763b09586ba8679f08fc"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 4:Crystal Diffraction"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.1 , Page no:75"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"lambda1=2.6; #in Angstrom (wavelength)\n",
"theta=20; #in Degree (angle)\n",
"n=2;\n",
"\n",
"#calculate\n",
"lambda1=lambda1*1E-10; #since lambda is in Angstrom\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore d=n(lambda)/2sin(theta)\n",
"d=n*lambda1/(2*math.sin(math.radians(theta)));\n",
"\n",
"#result\n",
"print\"The spacing constant is d=\",d,\"m\";\n",
"print\"\\t\\t\\td=\",d*10**10,\"Angstrom\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The spacing constant is d= 7.60189144042e-10 m\n",
"\t\t\td= 7.60189144042 Angstrom\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.2 , Page no:75"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"h=1;k=1;l=0; #miller indices\n",
"a=0.26; #in nanometer (lattice constant)\n",
"lambda1=0.065; #in nanometer (wavelength)\n",
"n=2; #order\n",
"\n",
"#calculate\n",
"d=a/math.sqrt(h**2+k**2+l**2); #calculation of interlattice spacing\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"theta=math.asin(n*lambda1/(2*d));\n",
"theta1=theta*180/3.14;\n",
"\n",
"#result\n",
"print\"The glancing angle is =\",round(theta1,2),\"degree\";\n",
"print \"Note: there is slight variation in the answer due to round off error\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The glancing angle is = 20.72 degree\n",
"Note: there is slight variation in the answer due to round off error\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.3 , Page no:75"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"d=3.04E-10; #in mm (spacing constant)\n",
"lambda1=0.79; #in Angstrom (wavelength)\n",
"n=3; #order\n",
"\n",
"#calculate\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"lambda2=lambda1*1E-10; #since lambda is in angstrom\n",
"theta=math.asin(n*lambda2/(2*d));\n",
"theta1=theta*180/3.14;\n",
"\n",
"#result\n",
"print\"The glancing angle is\",round(theta1,3),\"degree\";\n",
"print \"Note: In question the value of d=3.04E-9 cm but in solution is using d=3.04E-10 m. So I have used d=3.04E-10 cm as used in the solution\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The glancing angle is 22.954 degree\n",
"Note: In question the value of d=3.04E-9 cm but in solution is using d=3.04E-10 m. So I have used d=3.04E-10 cm as used in the solution\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.4 , Page no:76"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"d=0.282; #in nanometer (spacing constant)\n",
"n=1; #order\n",
"theta=8.35; #in degree (glancing angle)\n",
"\n",
"#calculate\n",
"d=d*1E-9; #since d is in nanometer\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"lambda1=2*d*math.sin(math.radians(theta))/n; \n",
"lambda_1=lambda1*1E10; #changing unit from m to Angstrom\n",
"theta_1=90; #in degree (for maximum order theta=90)\n",
"n_max=2*d*math.sin(math.radians(theta_1))/lambda1; #calculation of maximum order. \n",
"\n",
"#result\n",
"print\"The wavelength =\",lambda1,\"m\";\n",
"print\"\\t\\t=\" ,round(lambda_1,3),\"Angstrom\";\n",
"print\"The maximum order possible is n=\",round(n_max);\n",
"print \"Note: In question value of theta=8 degree and 35 minutes but solution uses theta=8.35 degree.So I am using theta=8.35 degree\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The wavelength = 8.19038939236e-11 m\n",
"\t\t= 0.819 Angstrom\n",
"The maximum order possible is n= 7.0\n",
"Note: In question value of theta=8 degree and 35 minutes but solution uses theta=8.35 degree.So I am using theta=8.35 degree\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.5 , Page no:76"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"theta=6; #in degree (glancing angle)\n",
"p=2170; #in Kg/m^3 (density)\n",
"M=58.46; #Molecular weight of NaCl\n",
"N=6.02E26; #in Kg-molecule (Avogadro's number)\n",
"n=1; #order\n",
"XU=1E-12; #since 1X.U.= 1E-12m\n",
"\n",
"#calculate\n",
"d=(M/(2*N*p))**(1/3); #calclation of lattice constant\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"lambda1=2*d*math.sin(math.radians(theta))/n; #calculation of wavelength\n",
"lambda2=lambda1/XU;\n",
"\n",
"#result\n",
"print\"The spacing constant is d=\",d,\"m\";\n",
"print\"The wavelength is =\",lambda1,\"m\";\n",
"print\"\\t\\t =\",lambda2,\"X.U\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The spacing constant is d= 2.81789104396e-10 m\n",
"The wavelength is = 5.89099640962e-11 m\n",
"\t\t = 58.9099640962 X.U\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.6 , Page no:77"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"h=1;k=1;l=1; #miller indices\n",
"a=5.63; #in Angstrom (lattice constant)\n",
"theta=27.5; #in degree (Glancing angle)\n",
"n=1; #order\n",
"H=6.625E-34; #in J-s (Plank's constant)\n",
"c=3E8; #in m/s (velocity of light)\n",
"e=1.6E-19; #charge of electron\n",
"\n",
"#calculate\n",
"d=a/math.sqrt(h**2+k**2+l**2); #calculation for interplanar spacing\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"lambda1=2*d*math.sin(math.radians(theta))/n; #calculation for wavelength\n",
"E=H*c/(lambda1*1E-10); #calculation of Energy\n",
"E1=E/e; #changing unit from J to eV\n",
"\n",
"#result\n",
"print\"The lattice spacing is d=\",round(d,2),\"Angstrom\";\n",
"print\"The wavelength is =\",round(lambda1),\"Angstrom\";\n",
"print\"The energy of X-rays is E=\",E,\"J\";\n",
"print\"\\t\\t\\tE=\",E1,\"eV\";\n",
"print \"Note: c=3E8 m/s but in solution c=3E10 m/s \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The lattice spacing is d= 3.25 Angstrom\n",
"The wavelength is = 3.0 Angstrom\n",
"The energy of X-rays is E= 6.62100284311e-16 J\n",
"\t\t\tE= 4138.12677695 eV\n",
"Note: c=3E8 m/s but in solution c=3E10 m/s \n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.7 , Page no:77"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"V=344; #in V (accelerating voltage)\n",
"theta=60; #in degree (glancing angle)\n",
"m=9.1E-31; #in Kg (mass of electron)\n",
"h=6.625e-34; #in J-s (Plank's constant)\n",
"n=1; #order\n",
"e=1.6E-19; #charge on electron\n",
"\n",
"#calculate\n",
"#Since K=m*v^2/2=e*V\n",
"#therefore v=sqrt(2*e*V/m)\n",
"#since lambda=h/(m*v)\n",
"#therefore we have lambda=h/sqrt(2*m*e*V)\n",
"lambda1=h/math.sqrt(2*m*e*V); #calculation of lambda\n",
"lambda2=lambda1*1E10; #changing unit from m to Angstrom\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"d=n*lambda2/(2*math.sin(math.radians(theta)));\n",
"\n",
"#result\n",
"print\"The wavelength is =\",lambda1,\"m\";\n",
"print\"\\t\\t =\",round(lambda2,2),\"Angstrom\";\n",
"print\"The interplanar spacing is d=\",round(d,2),\"Angstrom\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The wavelength is = 6.61928340764e-11 m\n",
"\t\t = 0.66 Angstrom\n",
"The interplanar spacing is d= 0.38 Angstrom\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.8 , Page no:78"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"K=0.02; #in eV (kinetic energy)\n",
"d=2.0; #in Angstrom (Bragg's spacing)\n",
"m=1.00898; #in amu (mass of neutron)\n",
"amu=1.66E-27; #in Kg (1amu=1.66E-27 Kg)\n",
"h=6.625e-34; #in J-s (Plank's constant)\n",
"n=1; #order\n",
"e=1.6E-19; #charge on electron\n",
"\n",
"#calculate\n",
"#Since K=m*v^2/2\n",
"#therefore v=sqrt(2*K/m)\n",
"#since lambda=h/(m*v)\n",
"#therefore we have lambda=h/sqrt(2*m*K)\n",
"m=m*amu; #changing unit from amu to Kg\n",
"K=K*e; #changing unit to J from eV\n",
"lambda1=h/math.sqrt(2*m*K); #calculation of lambda\n",
"lambda2=lambda1*1E10; #changing unit from m to Angstrom\n",
"theta=math.asin(n*lambda2/(2*d)); #calculation of angle of first order diffraction maximum\n",
"theta1=theta*180/3.14;\n",
"#result\n",
"print\"The wavelength is =\",lambda1,\"m\";\n",
"print\"\\t \\t =\",round(lambda2),\"Angstrom\";\n",
"print\"The angle of first order diffraction maximum is \",round(theta1),\"Degree\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The wavelength is = 2.02348771817e-10 m\n",
"\t \t = 2.0 Angstrom\n",
"The angle of first order diffraction maximum is 30.0 Degree\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.9 , Page no:79"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#given\n",
"lambda1=0.586; #in Angstrom (wavelength of X-rays)\n",
"n1=1; n2=2; n3=3; #orders of diffraction\n",
"theta1=5+(58/60); #in degree (Glancing angle for first order of diffraction)\n",
"theta2=12+(01/60); #in degree (Glancing angle for second order of diffraction)\n",
"theta3=18+(12/60); #in degree (Glancing angle for third order of diffraction)\n",
"\n",
"#calculate\n",
"K1=math.sin(math.radians(theta1));\n",
"K2=math.sin(math.radians(theta2));\n",
"K3=math.sin(math.radians(theta3));\n",
"#Since 2dsin(theta)=n(lambda)\n",
"#therefore we have\n",
"d1=n1*lambda1/(2*K1);\n",
"d2=n2*lambda1/(2*K2);\n",
"d3=n3*lambda1/(2*K3);\n",
"d1=d1*1E-10; #changing unit from Angstrom to m\n",
"d2=d2*1E-10; #changing unit from Angstrom to m\n",
"d3=d3*1E-10; #changing unit from Angstrom to m\n",
"d=(d1+d2+d3)/3;\n",
"\n",
"#result\n",
"print\"The value of sine of different angle of diffraction is \\nK1=\",K1;\n",
"print\"K2=\",K2;\n",
"print\"K3=\",K3;\n",
"#Taking the ratios of K1:K2:K3\n",
"#We get K1:K2:K3=1:2:3\n",
"#Therefore we have\n",
"print\"Or we have K1:K2:K3=1:2:3\";\n",
"print\"Hence these angles of incidence are for Ist, 2nd and 3rd order reflections respectively\";\n",
"print\"The spacing constants are \\nd1=\",d1;\n",
"print\"d2=\",d2;\n",
"print\"d3=\",d3;\n",
"print\"The mean value of crystal spacing is d=\",d,\"m\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The value of sine of different angle of diffraction is \n",
"K1= 0.103949856225\n",
"K2= 0.208196213621\n",
"K3= 0.312334918512\n",
"Or we have K1:K2:K3=1:2:3\n",
"Hence these angles of incidence are for Ist, 2nd and 3rd order reflections respectively\n",
"The spacing constants are \n",
"d1= 2.81866671719e-10\n",
"d2= 2.81465253286e-10\n",
"d3= 2.81428667722e-10\n",
"The mean value of crystal spacing is d= 2.81586864243e-10 m\n"
]
}
],
"prompt_number": 9
}
],
"metadata": {}
}
]
}
|