ABSTRACT
Table 432 shows the selected references for data for NF3
431 Selected References for Data 285 432 Total Scattering Cross Sections 286 433 Differential Scattering Cross Sections 286 434 Elastic and Momentum Transfer Cross Sections 286 435 Ion Appearance Potentials 286 436 Ionization Cross Sections 287 437 Attachment Processes 287 438 Attachment Rates 288 439 Attachment Cross Sections 289 4310 Attachment Coefficients 290 References 290
TABLE 43.1 Vibrational Modes and Energies for NF3 Designation Type of Motion Energy (meV)
ν1 Symmetrical stretch 128 ν2 Symmetrical deformation 802 ν3 Degenerate stretch 1125 ν4 Degenerate deformation 610
TABLE 43.2 Selected References for Data
Parameter Range: eV, (Td) Reference
Total scattering cross section
05-370 Szmytkowski et al. (2004)
Attachment cross section 0-6 Nandi et al. (2001) Ionization cross section 13-220 Haaland et al. (2001) Elastic scattering cross section
15-100 Boesten et al. (1996)
Attachment rate 002-005 Miller et al. (1995) Total scattering cross section
0-10 Rescigno (1995)
Ionization cross section 13-220 Tarnovsky et al. (1994) Attachment coefficients 01-10 Ushiroda et al (1990)
Attachment coefficients 03-300 Lakdawala and Moruzzi (1980)
Attachment coefficients 1-16 Nygaard et al. (1979) Attachment rate 0025 Sides and Tiernan (1977) Attachment rate 0025 Mothes et al. (1972) Ionization energy 11-18 Reese and Diebler (1956)
Note:Bold font indicates experimental study
sections The highlights of the cross sections are
1 The total scattering cross section increases from 05 eV to a peak at 27 eV, attributed to shape resonance, that is, the electron attaches to the neutral
2 The total scattering cross section has a minimum at ~10 eV and shows a second, broad peak in the region of 30-45 eVThis peak is attributed mostly to elastic scattering with contributions from ionization and dissociative excitation
3 Above the second peak, the cross section decreases, up to ~370 eV according to QT~ε−1/2
Figure 432 shows the three-dimensional variation of the differential scattering cross section as a function of angle of scattering and electron energy in the 15-100 eV range (Boesten et al, 1996)At low energies, the dependence of the differential scattering cross section on the angle of scattering is relatively small, with a small evidence of forward scatteringAt higher energies, a minimum is observed in the range of 120° to 90° as the energy is increased from ~5 to 100 eV The many ridges and valleys observed (Figure 432) are not satisfactorily explained so far
Table 434 and Figure 433 show the integral elastic and momentum transfer cross sections for NF3 (Boesten et al, 1996)
Ion appearance potentials and relative abundances are shown in Table 435 (Reese and Dibeler, 1956)The probable products of electron impact are also shown
0.1
0 1 10 100 1000
Energy (eV)
Total scattering (NF3)
Nitrogen trifluoride
Q T (1
m 2 )
1.43
1.5 eV
10 20
TABLE 43.3 Total Scattering Cross Sections for NF3 Energy (eV)
QT (10-20 m2)
Energy (eV)
QT (10-20 m2)
Energy (eV)
QT (10-20 m2)
05 159 35 265 27 189
06 166 37 258 30 192
08 181 40 249 35 194
10 196 45 227 40 194
12 212 50 209 45 194
14 227 55 195 50 193
15 233 60 185 60 188
16 240 65 176 70 183
17 248 70 172 80 173
18 252 75 170 90 166
19 254 80 168 100 161
20 263 85 167 110 156
21 269 9 167 120 151
22 274 95 167 140 141
23 275 10 167 160 131
24 275 11 166 180 123
25 277 12 167 200 115
26 278 14 169 220 110
27 280 16 172 250 104
28 279 18 176 275 994
29 278 20 179 300 963
30 277 22 182 350 918
32 272 25 186 370 907
Source:Adapted from Szmytkowski, Cet al, Phys. Rev. A, 70, 032707, 2004
Ionization cross sections measured by Haaland et al (2004) are shown in Table 436 and Figure 434
Reactions that occur at thermal energy are (sides and Tiernan, 1977)
e + NF3 → NF2 + F− (431)
→ NF + F + F− (432)
→ N + F + F + F− (433)
→ F2 + NF− (434)
→ F + F + NF− (435)
→ NF + F2− (436)
0 20 40 60 80 100 Energy (eV)
Q e l,Q
M (1
m 2 )
Nitrogen trifluoride (NF3)
Momentum transfer Elastic
Qel
QM
Ion Species Appearance
Potential (eV)
Relative Abundance
at 70 eV Products
F− ~0 — F− + NF2 F2-~0 — ?
