ABSTRACT
Drift velocity 2-100 Saelee and Lucas (1979) Excitation cross section 2-1500 Chen and Gallagher (1978) Excitation rates 025 Deutsch (1973) Ionization coefficient (150-1800) Garamoon and Surplice (1973) Momentum transfer cross section 001-10 Nighan and Postma (1972)b
Total scattering cross section 03-9 Visconti et al. (1971)c
Excitation cross section 2-30 Moiseiwitsch and Smith (1968) Ionization cross section 5-100 Nygaard (1968) Ionization cross section 5-500 McFarland and Kinney (1965) Ionization cross section 300, 500 Brink (1964) Drift velocity (28-60) Chanin and Steen (1964) Ionization cross section 0-700 Tate and Smith (1934) Total cross section 0-400 Brode (1929)
Note:Bold font indicates experimental study a An interesting approach was adopted to derive the momentum transfer cross sections in the energy range 005-2 eV Six quantities, all of which involve the
momentum transfer cross sections, were consideredThe six quantities are (a) width of the electron cyclotron resonance, (b) attenuation of microwaves, (c) electrical conductivity in both equilibrium and nonequilibrium pure Cs or Ar-Cs plasmas, (d) electron thermal conductivity in a strong magnetic field, (e) perpendicular electrical conductivity in a strong magnetic field, and (f) electron drift velocityAn algorithm was generated to obtain the best fit with the experimental dataThe Ramsauer-Townsend minimum was observed at 0278 eV and the minimum cross section was 72 × 10−20 m2 Two maxima are observed at 015 and 045 eVTabulated results are given in terms of the velocity of the electronThe conversion factor is ε (eV) = [W(107) cm s−1/593]2
b Electron drift velocity was analyzed to obtain the momentum transfer cross sections in the energy range 0-1 eV The maximum cross section of 2500 × 10−20 m2 is observed at 025 eV
c Total cross sections are provided for cesium, rubidium, and potassium in the energy range 0-10 eV by the crossed beam atom recoil technique which comprises of measuring the energy of scattered atoms
Ramsauer-Townsend minimum occurs at 008 eV (Crown and Russek, 1965)The excitation cross section to levels 62P1/2 (threshold 139 eV) (Saelee and Lucas, 1979) and 62P3/2 (threshold 145 eV) are the major contributions and according to Chen and Gallagher (1978) the total is 15 times the latter
Figure 22 shows the optical excitation cross sections for resonance for K, Rb, and Cs up to 1500 eV
Tables 22, 23 and Figure 23 show the ionization cross sectionFigure 23 also includes excitation cross section
A recent review (Borovik and Kupliauskiene, 2009) shows that Nygaard’s data are still the most recent one available
Figure 24 presents transport parameters for the Cs atom
0.1 1.0 10 100 1000
Cs
QTQM
Qex Qiz
5 4
Energy (eV)
Cr os
ss ec
tio n
(1 0-
2 )
1 10 100 1000 10,000
Energy (eV)
Q e x(1
m 2 )
1 10 100 1000 10,000 Energy (eV)
Cr os
ss ec
tio n
(1 0-
2 )
0.1
0.01
Cesium (Cs)
Excitation lonization
Cross Section for Cs Atom
Energy (eV) 50 100 200 300 400 500
Qi (10−20 m2) 88 70 545 40 34 28
Source:Adapted from McFarland, RHand JDKinney, Phys. Rev, 137, A1058, 1965
TABLE 2.3 Ionization Cross Sections for Cs Atom, Digitized
Energy (eV) Qi (10−20 m2) Energy (eV) Qi (10−20 m2)
425 004 2814 948
508 179 3430 938
549 274 4024 916
591 381 4619 893
632 467 5129 871
695 570 5724 840
800 685 6318 809
863 762 7168 769
968 835 7805 733
1137 895 8528 698
1349 929 9037 671
1519 942 9441 662
1795 928 9717 644
2262 945 9972 639
Source:Adapted from Nygaard, K J, J. Chem. Phys, 49, 1995, 1968
Table 24 and Figure 25 show the results of a single study (Garamoon and Surplice, 1973)
1 10 1000100
10-2
10-1
E/N (Td)
En er
gy (V
)
W (m
/s )
Cesium (Cs)
Mean ener. W
TABLE 2.4 Reduced Ionization Coefficient for Cs Atom
E/N (Td) α/N (10−20 m2) E/N (Td) α/N (10−20 m2)
130 1285 600 1821
160 1520 630 1832
190 1754 660 1845
220 1884 700 1863
250 1858 800 1885
280 1812 900 1873
310 1778 1000 1887
340 1770 1100 1962
370 1762 1200 2070
400 1784 1300 2173
430 1814 1400 2286
460 1820 1500 2471
500 1811 1600 2685
530 1808 1700 2842
560 1810
Source:Adapted from Garamoon, AAWMand NASurplice, J. Phys. D: Appl. Phys, 6, 206, 1973
0.08
0.04
0 1000 10,000
Cesium (Cs)
α/N
E/N (Td)
η
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