Spectral Characteristics of Cesium



Neutral Cesium has thermal lines extending from the near ultra-violet, far down into the infra-red. Strong lines occur from 3876 to 34900 angstorms. There isn't really a lower limit (in energy). You can go as far down into the IR as you want by jumping electrons to higher and higher orbitals. It's just that the lines stop being very observable after a while. Single Ionized cesium has lines in the vacuum ultraviolet starting at 591 Angstroms. The following are some of the prominant lines for neutral cesium

  
  Wavelength   Relative
  Angstroms    Intensity
  
  3876.15           2100    These are in the near ultraviolet
  3888.61            600
  
  4555.28           1000    The famous blue lines, used for
  4593.17            450    spectroscopic identification
  
  5465.94             60    A bunch of relatively weak
  5502.88             37    greenish lines.
  5635.21            100
  5664.02            210
  5745.72             27
  
  5838.83             59    A couple of yellow lines
  5845.14            300
  
  6010.49            640    Lines in the orange
  6034.09             86
  6213.10           1000
  6217.60            170
  6354.55            320
  
  6586.51            490    A couple of strong and
  6628.66             97    some weaker red lines
  6723.28           3300
  6824.65            200
  6870.45            300
  6973.30           4800
  6983.49            980
   .
   .
   .
  And on down through the infrared
   .
   .
   .
  8521.13          59000    Two exceedingly strong ones,
  8943.47          61000    used for spectrascopic ID
   .
   .
   .
  
  

Note that this spectrum looks like it would appear be mostly red to the eye, given the number of strong lines around red, whereas the actual appearance of burning cesium or flames colored with it tends from blue towards lavender and reddish violet. The explanation is that there are a number of singly ionized lines that also figure in, depending on the temperature of the flame. The strongest of these, at 4603.79, plus other blue and green lines add significantly to the bluish appearance. Some prominant lines from the singly ionized spectrum follow. Note that the relative intensities don't necessarily compare directly with those for the neutral atoms.

  
  Wavelength   Relative
  Angstroms    Intensity
   .
   .
   .
  Lots of stuff up in the UV
   .
   .
   .
  4039.85           8000    Violet line
  
  4264.70          14000    Strong blue lines
  4277.13          18000
  4501.55          12000
  4526.74          20000
  4603.79         100000
  4830.19          25000
  4870.04          19000
  
  4952.85          37000    Strong green lines
  5043.80          27000
  5227.04          75000
  5249.38          29000
  5274.05          11000
  5349.13          10000
  5370.99          22000
  5563.02          39000
  
  5831.14          24000    A yellow line
  
  5925.63          51000    A couple of orange ones
  6128.61           9800
  
  6495.53           8300    And some red ones
  6536.44          10000
  6955.50          37000
  6979.67          16000
   .
   .
   .
  And down through the IR
   .
   .
   .
  

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