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   "source": [
    "# 2: Molecular Spectroscopy"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example number 1, Page number 56"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "energy is 4.75 *10**-4 eV\n",
      "angular velocity is 10.21 *10**11 rad/sec\n",
      "answer in the book varies due to rounding off errors\n"
     ]
    }
   ],
   "source": [
    "#importing modules\n",
    "import math\n",
    "from __future__ import division\n",
    "\n",
    "#Variable declaration   \n",
    "h=6.62*10**-34;        #planck's constant\n",
    "I=1.46*10**-46;        #moment of inertia(kg-m**2)\n",
    "e=1.6*10**-19;      #charge(coulomb)\n",
    "\n",
    "#Calculations\n",
    "Er=2*(h**2)/(8*math.pi**2*I*e);        #energy(eV)\n",
    "omega=math.sqrt(2*Er*e/I);       #angular velocity(rad/sec)\n",
    "\n",
    "#Result\n",
    "print \"energy is\",round(Er*10**4,2),\"*10**-4 eV\"\n",
    "print \"angular velocity is\",round(omega*10**-11,2),\"*10**11 rad/sec\"\n",
    "print \"answer in the book varies due to rounding off errors\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example number 2, Page number 62"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "frequency of vibration is 2.04 *10**13 Hertz\n",
      "spacing between energy levels is 8.44 *10**-2 eV\n"
     ]
    }
   ],
   "source": [
    "#importing modules\n",
    "import math\n",
    "from __future__ import division\n",
    "\n",
    "#Variable declaration   \n",
    "h=6.63*10**-34;        #planck's constant\n",
    "K=187;       #force constant(N/m)\n",
    "mew=1.14*10**-26;         #reduced mass(kg)\n",
    "c=6.242*10**18;       #conversion factor\n",
    "\n",
    "#Calculations\n",
    "vnew=math.sqrt(K/mew)/(2*math.pi);          #frequency of vibration(Hertz)\n",
    "delta_E=h*vnew;        #spacing between energy levels(J)\n",
    "delta_E=delta_E*c;        #spacing between energy levels(eV)\n",
    "\n",
    "#Result\n",
    "print \"frequency of vibration is\",round(vnew/10**13,2),\"*10**13 Hertz\"\n",
    "print \"spacing between energy levels is\",round(delta_E*10**2,2),\"*10**-2 eV\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example number 3, Page number 68"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "wavelength of antistokes line 5401 angstrom\n"
     ]
    }
   ],
   "source": [
    "#importing modules\n",
    "import math\n",
    "from __future__ import division\n",
    "\n",
    "#Variable declaration   \n",
    "lamda0=5460*10**-8;      #wavelength(cm)\n",
    "lamdas=5520*10**-8;      #wavelength(cm)\n",
    "\n",
    "#Calculations\n",
    "new0=1/lamda0;       #frequency(cm-1)\n",
    "news=1/lamdas;       #frequency(cm-1)\n",
    "delta_new=new0-news;        #difference in frequency(cm-1)\n",
    "new_as=delta_new+new0;      #frequency of anti-stokes line(cm-1)\n",
    "lamda_as=1*10**8/new_as;          #wavelength of antistokes line(angstrom)\n",
    "\n",
    "#Result\n",
    "print \"wavelength of antistokes line\",int(lamda_as),\"angstrom\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example number 4, Page number 68"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "raman shift is 459.2 *10**2 m-1\n",
      "wavelength of antistokes line 4272.5 angstrom\n"
     ]
    }
   ],
   "source": [
    "#importing modules\n",
    "import math\n",
    "from __future__ import division\n",
    "\n",
    "#Variable declaration   \n",
    "lamda0=4358*10**-10;      #wavelength(m)\n",
    "lamda1=4447*10**-10;      #wavelength(m)\n",
    "\n",
    "#Calculations\n",
    "new0=1/lamda0;       #frequency(m-1)\n",
    "new1=1/lamda1;       #frequency(m-1)\n",
    "rs=new0-new1;        #raman shift(m-1)\n",
    "new_as=new0+rs;      #frequency of anti-stokes line(cm-1)\n",
    "lamda_as=1*10**10/new_as;          #wavelength of antistokes line(angstrom)\n",
    "\n",
    "#Result\n",
    "print \"raman shift is\",round(rs/10**2,1),\"*10**2 m-1\"\n",
    "print \"wavelength of antistokes line\",round(lamda_as,1),\"angstrom\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example number 5, Page number 71"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "ratio of wave numbers is 1 : 0.52 : 0.31\n"
     ]
    }
   ],
   "source": [
    "#importing modules\n",
    "import math\n",
    "from __future__ import division\n",
    "\n",
    "#Variable declaration   \n",
    "K1=4141.3;         #wave number of HF(cm-1)\n",
    "K2=2988.9;         #wave number of HCl(cm-1)\n",
    "K3=2309.5;         #wave number of HI(cm-1)\n",
    "c=1;              #assume as common factor in ratio\n",
    "\n",
    "#Calculations\n",
    "a=(K2/K1)**2;       #ratio of wave numbers of HF and HCl\n",
    "b=(K3/K1)**2;       #ratio of wave numbers of HF and HI\n",
    "\n",
    "#Result\n",
    "print \"ratio of wave numbers is\",c,\":\",round(a,2),\":\",round(b,2)"
   ]
  }
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