A=20Ne (1983AJ01)

Excitation functions for reactions (a) and (b) have been measured for E_c.m. = 3 to 10 MeV: large resonant structures are observed in reaction (b). Particularly pronounced structures [~ 0.6 MeV] corresponding to E_x ~ 38 MeV (α₀) and 38.6 MeV (α to ¹⁶O*(7.0, 10.3, 16.2 [u]) are reported (1978MA07). The elastic excitation function has also been studied for E(¹⁰B) = 8 to 30 MeV by (1975DI08). See also (1978AJ03), ¹⁰B in (1979AJ01) and ¹⁶O in (1982AJ01).

2. ¹⁰B(¹⁴N, α)²⁰Ne Q_m = 19.5332

At E(¹⁴N) = 25 and 35 MeV angular distributions of the α-particles to ²⁰Ne*(0, 1.63, 4.25, 4.97, 5.62, 5.78, 7.00, 7.17, 7.42, 7.83, 8.45, 8.78, 9.03 + 9.12, 9.99, 10.26, 10.61) have been measured by (1974MA38, 1975LE23). The average behavior of the cross section is generally well described by a statistical mechanism but the reaction mechanism is not purely statistical (1975LE23). Angular distributions are also reported at E(¹⁴N) = 23.5 MeV (1978DU08: α₀, α₁, α₂, α₄₊₅). For experiments relating to the compound nucleus see (1978AJ03) and (1977MA33, 1978DU08, 1978DU23, 1978WU1C, 1981BA26). See also (1976KL1B, 1978HO1C).

3. ¹⁰B(¹⁶O, ⁶Li)²⁰Ne Q_m = 0.270

At E(¹⁶O) = 19.5, 24.3, 31.5, 35.9 and 42 MeV angular distributions have been measured for the ⁶Li ions corresponding to transitions to ²⁰Ne*(0, 1.63, 4.25, 4.97, 5.62 + 5.78, 6.7 - 7.2). Hauser-Feshbach calculations are generally in good agreement with the data (1976LO03). See also (1977MO1A) and (1978AJ03).

4. ¹¹B(¹⁶O, ⁷Li)²⁰Ne Q_m = -3.934

At E(¹¹B) = 115 MeV, angular distributions are reported to ²⁰Ne*(7.17, 8.78, 10.25, 11.95, 15.4). ²⁰Ne*(8.78, 15.4, 17.3, 21.0 ± 0.07, 22.78 ± 0.06) are particularly strongly populated. It is suggested that these five states have J^π = 6⁺, 7^-, (8⁺), 9^- and 9^- (1979BR03, 1979RA10). See also (1978AJ03).

5. ¹²C(⁹Be, n)²⁰Ne Q_m = 10.3196

At E(⁹Be) = 16 and 24 MeV angular distributions have been measured for ²⁰Ne*(7.3 ± 0.4, 9.2 ± 0.4, 10.9 ± 0.3, 12.2 ± 0.3, 15.7 ± 0.3). It is suggested that ²⁰Ne*(7.3, 9.2, 12.2, 15.7) correspond to the 0⁺ + 2⁺, 4⁺, 6⁺ and 8⁺ members of the K^π = 0⁺₃ band (1981SU01).

6. (a) ¹²C(¹⁰B, d)²⁰Ne Q_m = 5.9589
(b) ¹²C(¹¹B, t)²⁰Ne Q_m = 0.7610

At E(¹²C) = 45 MeV the population of states of ²⁰Ne with E_x = 8.45, 8.78, 9.03, 10.61, 10.67, 10.99, 11.01, 11.66, 11.94, 12.14, 12.39, 12.58, 12.73, 13.05, 13.17, 13.34 [7^-], 13.69, 13.91, 14.29, 14.36, 14.81, 15.17 [6⁺], 15.38 [7^-], 15.71 [(7, 8)], 15.89 [(7)], 16.16, 16.22, 16.51 [(8)], 16.73, 17.39 [9^-], 18.18 and 18.32 MeV is reported. [Values in brackets are J^π suggested on basis of Hauser-Feshbach calculations. The states in italics are well resolved: the authors indicate ± 20 keV for such states.] The relative intensities of the groups to ²⁰Ne*(17.39, 15.38) [J^π = 9^-, 7^-] argue against the existence of a superband (1976KL03). At E(¹⁰B) = 20.0 and 20.5 MeV angular distributions are reported to the 2⁺ states ²⁰Ne*(7.42, 7.83). ²⁰Ne*(7.83) is more strongly populated than ²⁰Ne*(7.42), and it, and ²⁰Ne*(7.19), have integrated cross sections which deviate from the (2J + 1) "rule" by a factor of about two (1978FO01). See also (1978AJ03) and (1976KL1B, 1978HO1C).

7. ¹²C(¹²C, α)²⁰Ne Q_m = 4.6181

Double and triple (α, α, γ) correlations and γ-ray branching measurements [see Table 20.18 (in PDF or PS)] lead to the J^π assignments shown in Table 20.19 (in PDF or PS), which also shows level assignments to rotational bands. Angular distributions have been reported at E(¹²C) = 4.9 to 51 MeV [see (1978AJ03)] and at E(¹²C) = 6.3 to 6.6 MeV (1980IS1B; α₀, α₁), 10 MeV (1981BE60; α₀), 12 MeV (1981BE60; α₁), 19.3 MeV (1980AN08; α₀) and 33 to 40 MeV (1982FO03; α₀). τ_m for ²⁰Ne*(4.25) is 95 ± 13 fsec (1982SP02) [see also for g-value, the "Ground state of ²⁰Ne" section here].

The yields of various groups of α-particles and their relevance to states of ²⁴Mg, and fusion cross sections, have been studied by many groups: see (1978AJ03) for the earlier work and (1977CI1E, 1977CO25, 1977PA1G, 1978TR06, 1979DE08, 1980AN08, 1980CO03, 1980ER06, 1980IS1B, 1980KO02, 1981BE60, 1982FO03). See also (1978MA2J), (1978SC1G, 1979GO1C), (1978RO1D, 1978RO1L, 1981BE60, 1982IB1A; astrophys.) and (1972NO01, 1977AB1E, 1978BR12, 1978MA1G, 1978TO12, 1980GA18, 1981SU1J; theor.).

8. ¹²C(¹⁴N, ⁶Li)²⁰Ne Q_m = -4.181

Angular distributions of the ⁶Li ions to many states of ²⁰Ne below 17.5 MeV have been reported for E(¹⁴N) = 30 to 78 MeV and E(¹²C) = 67.2 MeV. Compound nucleus formation appears to be dominant. In the latter work (1973BE11) ²⁰Ne*(16.67, 17.38, 18.11, 19.16, 19.6) are particularly strongly populated. For complete references see (1978AJ03). See also (1977ST34) and (1976KL1B, 1978HO1C).

9. (a) ¹²C(¹⁸O, ¹⁰Be)²⁰Ne Q_m = -6.3476
(b) ¹²C(¹⁹F, ¹¹B)²⁰Ne Q_m = -3.1122

See (1978AJ03). See also (1981YO05; theor.).

10. ¹³C(¹³C, α2n)²⁰Ne Q_m = -5.2747

See (1982CH05).

11. (a) ¹⁴N(⁶Li, p)¹⁹F Q_m = 11.1491 E_b = 23.994
(b) ¹⁴N(⁶Li, d)¹⁸F Q_m = 2.942
(c) ¹⁴N(⁶Li, α)¹⁶O Q_m = 19.2628

Yield curves for E(⁶Li) = 4.1 to 9.2 MeV do not show any structure: see (1978AJ03).

12. (a) ¹⁴N(¹²C, ⁶Li)²⁰Ne Q_m = -4.181
(b) ¹⁵N(¹²C, ⁷Li)²⁰Ne Q_m = -7.764

For reaction (a) see (1979GO1C). For reaction (b) see (1979RA10).

13. ¹⁶O(α, γ)²⁰Ne Q_m = 4.7309

Observed resonances in the yield of capture γ-rays over the range E_α = 0.8 to 10 MeV are displayed in Table 20.20 (in PDF or PS). Information on the character of the radiative decay is shown in Table 20.18 (in PDF or PS). ²⁰Ne*(11.261) [J^π = 1⁺; T = 1] is not observed: Γ_α < 3 × 10^-5 eV, leading to |〈1⁺V_PNC1^-〉| < 1.2 eV (1980FIZX). ²⁰Ne*(12.25) is the 3^-; T = 1 analog of ²⁰F*(1.97) (1980FI01). See also (1978AJ03, 1979NO11), (1982IB1A; astrophys.) and (1982DU1A; theor.).

14. (a) ¹⁶O(α, α)¹⁶O E_b = 4.7309
(b) ¹⁶O(α, 2α)¹²C Q_m = -7.1620

Excitation functions have been measured over a wide range for elastically and inelastically scattered α-particles, and γ-rays from the decay of ¹⁶O*(6.13, 6.92, 7.12): see (1978AJ03) and (1981GA35; 9.5 to 9.8 MeV; α₁), (1979BI10; 14.6 to 20.4 MeV; α₀ → α₅), (1979AR05; 17.5 to 22.7 MeV; α₀) and (1978CO10; 27 to 33.6 MeV; α₀).

A number of anomalies are observed: they are displayed in Table 20.21 (in PDF or PS): see, in particular, (1972HA07, 1973HA63, 1979BI10). (1979AR05) report structures in the range E_x = 18.7 - 22.9 MeV which are similar to those observed in ¹⁶O(⁶Li, d)²⁰Ne* → α + ¹⁶O_g.s.. The excitation function for α₀ at 178.1° shows a very strong structure at E_α ~ 29.5 MeV as does the excitation function for deuterons to ¹⁸F*(1.13) [J^π = 5⁺] (1978CO10, 1979CO1P): this anomalous scattering is correlated with a large variation in the degree of forward peaking of the (α, d) process.

For reaction (b) see (1980AJ01). For spallation reactions see (1978AJ03) and (1979VI05, 1980GO1E, 1980RE1B, 1981GOZY). See also (1981BE2D), (1979RA1C; astrophys.), (1977ST1X, 1982FI1C) and (1976PA20, 1977BA1N, 1977BA30, 1977IK1A, 1977TO1K, 1978FL1D, 1978KA22, 1978NO1B, 1978TA1A, 1978TH1A, 1978TO07, 1979AR05, 1979LE1B, 1979LE11, 1979VE09, 1979VE1C, 1980BA2K, 1980FL1C, 1980FU1F, 1980LE26, 1980TO1D, 1981AO01, 1981FI1B, 1981GY01, 1981WI01, 1982AO1B, 1982BI1D, 1982FL1A, 1982LA04; theor.).

15. ¹⁶O(α, n)¹⁹Ne Q_m = -12.1344 E_b = 4.7309

The excitation function (activation measurements) has been measured from threshold to E_α = 26.8 MeV (1973GR29). See also ¹⁹Ne, (1979BA48), (1979BU19; applied) and (1977GR18).

16. (a) ¹⁶O(α, p)¹⁹F Q_m = -8.1137 E_b = 4.7309
(b) ¹⁶O(α, d)¹⁸F Q_m = -16.3204

For reaction (a) see ¹⁹F. For reaction (b) see (1978CO10, 1979CO1P) and reaction 14.

17. ¹⁶O(⁶Li, d)²⁰Ne Q_m = 3.257

Deuteron groups have been observed to many states of ²⁰Ne: see Table 20.22 (in PDF or PS). Angular distributions have been measured for E(⁶Li) = 5.5 to 45 MeV [see (1978AJ03)] and at 20 and 38 MeV (1979AN01; d₀, d₁, d₂), 32 MeV (1979AN01; to all states shown in Table 20.23 (in PDF or PS) with E_x < 12.2 MeV, except ²⁰Ne*(10.7)), 42 MeV (1978BE43; d₀, d₁) and 75.4 MeV (1981TA06, 1981TA23; d to ²⁰Ne*(0, 1.63, 4.25, 5.78, 7.17, 8.78, 10.26, 11.95); S_α = 1.0, 0.96, 1.0, < 0.93, 0.49, 0.98, 0.88, 0.65, respectively; ²⁰Ne*(12.59, 13.90, 15.34, 17.30) were also populated. Reaction processes are discussed by (1979AN01). See also reaction 14 (1979AR05) and (1979ES01; d - γ involving ²⁰Ne*(1.63, 4.25)). For excitation functions see (1978HO01). See also (1980MA1N), (1977ST1X, 1979FU1N, 1980AN16) and (1981GY01, 1981LE10, 1981MA26, 1981XE01, 1982SE1E; theor.).

18. ¹⁶O(⁷Li, t)²⁰Ne Q_m = 2.264

States observed in this reaction are displayed in Table 20.22 (in PDF or PS). Angular distributions are reported at E(⁷Li) = 15 to 38 MeV [see (1978AJ03)] and at 50 and 68 MeV (1979BR03; to ²⁰Ne*(1.63, 4.25, 7.17, 8.78, 10.25, 15.4; see also for C²S). See also (1978AJ03).

19. ¹⁶O(⁹Be, αn)²⁰Ne Q_m = 3.1576

See (1979CH12, 1979CU1A).

20. (a) ¹⁶O(¹²C, ⁸Be)²⁰Ne Q_m = -2.6358
(b) ¹⁶O(¹²C, 2α)²⁰Ne Q_m = -2.5439

Angular distributions in reaction (a) have been measured for E(¹⁶O) = 27.1 to 46.4 MeV [see (1978AJ03)] and 28.5 to 35.2 MeV (1979VI08; g.s.), 43.2 to 53.0 MeV (1979JA19; g.s.) and 43.9 MeV (1979EB01; g.s.), and at E(¹²C) = 56 MeV (1976MA12), 22.7 to 32.4 MeV (1980HU07; g.s.) and 78 MeV (1979SA29; see Table 20.23 (in PDF or PS)). Γ_α₀/Γ measurements derived from ⁸Be - α correlations are listed in Table 20.22 (in PDF or PS) (1979SA29). For reaction (b) see (1978AJ03). For yield and cross-section measurements see (1977BR38, 1978CH15, 1978DI1F, 1978KA1L, 1978TA11, 1979EB01, 1979FLZW, 1979JA19, 1979KO03, 1979VI08, 1980HA1L, 1980HU07, 1980SI15). See also (1979GO1C, 1981RAZP) and (1981SA1J; theor.).

21. ¹⁶O(¹³C, ⁹Be)²⁰Ne Q_m = -5.9170

At E(¹³C) = 105 MeV angular distributions to ²⁰Ne*(1.63, 4.25, 8.78, 11.95, 15.34, 21.0) have been studied by (1979BR03): the first four states are the 2⁺, 4⁺, 6⁺ and 8⁺ members of the 0⁺ band; the two higher states [J^π = 7^-, 9^-] belong to the 0^- band whose band head is ²⁰Ne*(5.79). In addition distributions are reported to ²⁰Ne*(12.56, 15.9, 17.3) [J^π = 6⁺, 8⁺, 8⁺] (1979BR03). See also (1977FO1E, 1978AJ03).

22. ¹⁶O(¹⁴N, ¹⁰B)²⁰Ne Q_m = -6.8823

Angular distributions are reported at E(¹⁴N) = 76.2 MeV to ²⁰Ne*(0, 1.63, 4.25) (1977MO1A, 1979MO14). See also (1977FO1E, 1978AJ03).

23. ¹⁶O(¹⁶O, ¹²C)²⁰Ne Q_m = -2.4310

Angular distributions have been reported at E(¹⁶O) = 23.9 to 51.5 MeV [see (1978AJ03)] and at 35 MeV (1977KA26; ²⁰Ne*(0, 1.63)), 68 and 90 MeV (1977PO14, 1979PO14; ²⁰Ne*(0, 1.63, 4.25, 7.16, 8.45, 8.78, 10.26, 11.95)) and 95.2 MeV (1977MO1A, 1979MO14; ²⁰Ne*(0, 1.63)). (1979PO14, 1981PO1A) report that ²⁰Ne*(7.17, 8.45, 8.78) are strongly aligned and polarized along an axis perpendicular to the reaction plane. See also (1977PO14) and (1980BO1K; theor.). For partial fusion excitation functions see (1978FE04, 1978TS04, 1979KO15). See also (1978AJ03, 1978FI1E, 1979GO1C, 1981BR1P) and (1981KR09, 1982KO07; theor.).

24. (a) ¹⁶O(¹⁷O, ¹³C)²⁰Ne Q_m = -1.629
(b) ¹⁶O(¹⁸O, ¹⁴C)²⁰Ne Q_m = -1.4970

Angular distributions are reported at E(¹⁷O) = 35 MeV to ²⁰Ne*(0, 1.63) and at E(¹⁸O) = 36.1 MeV to ²⁰Ne*(0, 1.63, 4.25) (1977KA26). See also (1978AJ03).

25. ¹⁶O(¹⁹F, ¹⁵N)²⁰Ne Q_m = 0.7171

Angular distributions involving ²⁰Ne*(0, 1.63) have been studied at E(¹⁹F) = 36 MeV and E(¹⁶O) = 46, 58 and 68 MeV: see (1978AJ03) and (1980TA1K; theor.).

26. (a) ¹⁷O(³He, n)¹⁹Ne Q_m = 4.299 E_b = 21.164
(b) ¹⁷O(³He, t)¹⁷F Q_m = -2.780
(c) ¹⁷O(³He, ³He)¹⁷O
(d) ¹⁷O(³He, α)¹⁶O Q_m = 16.4335

For reaction (a) see ¹⁹Ne. The excitation function for α₀ [E(³He) = 7.0 to 10.0 MeV] shows a resonance corresponding to ²⁰Ne*(28.): see (1978AJ03). Polarization measurements are reported at E(pol. ³He) = 33 MeV for the t₀ group [reaction (b)], the ³He groups to ¹⁷O*(0, 0.87) [reaction (c)] and the α-groups to ¹⁶O*(12.97, 13.26) [reaction (d)] (1981BA1G, 1981KA1L, 1981LE1H). See also (1981RO1H).

27. ¹⁷O(α, n)²⁰Ne Q_m = 0.587

Angular distributions have been measured at E_α = 9.8 to 12.3 MeV for the n₁, n₂ and n₄₊₅ groups: see (1978AJ03). See also (1979BU19; applied) and (1981CH1K; astrophys.).

28. ¹⁷O(⁶Li, t)²⁰Ne Q_m = 5.370

See (1978AJ03).

29. (a) ¹⁷O(¹¹B, ⁸Li)²⁰Ne Q_m = -6.046
(b) ¹⁷O(¹²C, ⁹Be)²⁰Ne Q_m = -5.115

At E = 115 MeV the 8⁺ state at E_x = 11.95 MeV is particularly strongly populated in both reactions. ²⁰Ne*(1.63, 4.25, 7.16, 8.78, 10.3, 15.3, 15.9, 17.3, 21.1) are also observed (1979GO17).

30. ¹⁸O(³He, n)²⁰Ne Q_m = 13.1199

Angular distributions have been measured for E(³He) = 2.8 to 18.3 MeV. States of ²⁰Ne observed in this reaction are displayed in Table 20.23 (in PDF or PS). See also (1978AJ03).

31. ¹⁸O(¹¹B, ⁹Li)²⁰Ne Q_m = -10.027

At E(¹¹B) = 114 MeV, ²⁰Ne*(4.25, 8.9, 10.39, 15.43) are relatively strongly populated: see (1978AJ03).

32. ¹⁸O(¹²C, ¹⁰Be)²⁰Ne Q_m = -4.7816

At E(¹²C) = 46 MeV angular distributions to ²⁰Ne*(0, 1.63, 4.25) have been studied: the 2p spectroscopic factors are 0.58, 0.24 and 0.20, respectively (1975CO15).

33. ¹⁹F(p, γ)²⁰Ne Q_m = 12.8447

Over the range E_p = 2.9 to 12.8 MeV, the γ₀ and γ₁ yields are dominated by the E1 giant resonance (Γ ~ 6 MeV) with the γ₁ giant resonance displaced upward in energy. Strong well-correlated structure is observed with a characteristic Γ ~ 175 keV. Angular distributions taken over the energy range do not vary greatly with energy. They are incompatible with γ₀ and γ₁ coming from the same levels in ²⁰Ne (1967SE02). The 90° γ₀ yield for E_{pol. p} and E_p = 3.5 to 10 MeV has been measured: the results are interpreted in terms of four primary doorway states at E_x = 16.7, 17.8, 19.1 and 20.2 MeV (1980CA11).

The yield curve for 11.2 MeV γ-rays [from the decay of ²⁰Ne*(11.23), J^π = 1⁺, T = 1, to the ground state] displays a resonance at E_p = 4.090 ± 0.005 MeV [²⁰Ne*(16.73)]. The 11.2 MeV γ-rays are isotropic which is consistent with the presumed 0⁺ character of this lowest T = 2 state in ²⁰Ne: Γ_pΓ_γ/Γ ~ 0.5 eV. Since Γ_p/Γ (from the elastic scattering) is ~ 0.1, Γ_γ ~ 5 eV (1967KU06). For E_p = 5.65 to 6.21 MeV, the γ₀ and γ₁ yields are not resonant but the yield of 10.6 MeV γ-rays is resonant at 5.879 ± 0.007 MeV [Γ_c.m. = 9.5 ± 3 keV, Γ_p₀Γ_γ/Γ ~ 0.05 eV; Γ_γ ~ 0.3 eV]. The 10.6 MeV γ-ray is due to the cascade decay of ²⁰Ne*(18.43), J^π = 2⁺; T = 2 via ²⁰Ne*(12.22) to the 2⁺ state at 1.63 MeV (1972KU24). (1976MA01) have determined the upper limits to the strengths of the transitions to various states of ²⁰Ne from the 0⁺ and 2⁺ T = 2 states: these are displayed in Table 20.18 (in PDF or PS). No evidence is found for an isotensor transition amplitude (1976MA01). Resonances observed in this capture reaction are displayed in Table 20.24 (in PDF or PS). See also (1979HA1G) and (1978SC19, 1980SC1M; theor.).

34. (a) ¹⁹F(p, p)¹⁹F E_b = 12.8447
(b) ¹⁹F(p, p')¹⁹F*

The elastic scattering has been studied in the range E_p = 0.5 to 7.5 MeV and 24.9 to 46.3 MeV: see (1978AJ03). The observed anomalies are displayed in Table 20.25 (in PDF or PS).

Resonances for inelastic scattering [p₁ and p₂] are listed in Table 20.26 (in PDF or PS). In general the resonances observed are identical with those reported from other ¹⁹F + p reactions, although the relative intensities differ greatly. For reduced widths see Table 20.28 (in PDF or PS) in (1978AJ03). See also (1981KE1E; thick target yields; E_p = 1.75 to 2.75 MeV), (1980CU09, 1982FI1C) and (1977PH02; theor.).

35. ¹⁹F(p, n)¹⁹Ne Q_m = -4.0207 E_b = 12.8447

Observed resonances are displayed in Table 20.27 (in PDF or PS). See also (1980HU1D, 1980HU1J).

36. ¹⁹F(p, α)¹⁶O Q_m = 8.1137 E_b = 12.8447

Many resonances occur in this reaction. They are displayed in Tables 20.28 (in PDF or PS), 20.29 (in PDF or PS) and 20.30 (in PDF or PS) depending on whether they are observed in the α₀ yield [Table 20.28 (in PDF or PS)], in the α₁ [or α_π] yield to ¹⁶O*(6.05) [Table 20.29 (in PDF or PS)] or in the α₂, α₃ and α₄ yields [or in the yield of the γ-rays from ¹⁶O*(6.13, 6.92, 7.12)] [Table 20.30 (in PDF or PS)]. Resonances for α₀ and α₁ are required to have even J, even π or odd J, odd π, while the α₂, α₃ and α₄ resonances are all odd-even or even-odd, with the exception of the T = 2 resonance.

Listings of the earlier yield studies are given in (1972AJ02, 1978AJ03). A detailed discussion of the evidence leading to many of the J^π assignments is given in (1959AJ76). For values of θ² see Table 20.28 (in PDF or PS) in (1978AJ03). Recent measurements are reported by (1978DE1D, 1980CU09; 0.70 to 2.68 MeV; α₀, α_π, α₂, α₃, α₄), (1980DI03; 0.4 to 2.0 MeV; α₀, αγ) and (1977ST03; 12.4 to 18.0 MeV; α₀). In the latter work resonant structures with Γ ~ 0.5 to 1 MeV are reported at E_p = 13.0, 14.3, 15.3, 16.5, (17.5), corresponding to ²⁰Ne*(25.2, 26.4, 27.4, 28.5, (29.5)) (1977ST03).

Longitudinally polarized protons with E_{pol. p} ~ 0.67 MeV have been used to study ²⁰Ne*(13.48) [J^π = 1⁺; T = 1]: the maximum of the analyzing power was found to be (6.6 ± 2.4) × 10^-3. The parity mixing of the 670 keV resonance appears to be caused by the T = 0 continuum as well as by the 1^- state at E_x = 13.46 MeV (1981OH04). Anomalies are observed in α₀, α₁, α₂, α₄ and α₈ but not in α₃, α₅, α₇ and α₉ corresponding to the formation of the 2⁺; T = 2 state at 18.43 MeV [E_p = 5.88 MeV] (1972KU24). See also (1979SU13, 1979TR1G, 1981KE1E), (1978ZI1A, 1980DI03; applications) and (1977GA1H, 1980BI05; theor.).

37. ¹⁹F(p, ⁸Be)¹²C Q_m = 0.8599 E_b = 12.8447

See (1978AJ03).

38. ¹⁹F(d, n)²⁰Ne Q_m = 10.6200

Levels of ²⁰Ne derived from reported neutron groups are displayed in Table 20.31 (in PDF or PS). Angular distributions have been measured for E_d = 0.5 to 6.1 MeV: see (1972AJ02). See also (1978AJ03).

39. ¹⁹F(³He, d)²⁰Ne Q_m = 7.3511

Levels of ²⁰Ne observed in this reaction are displayed in Table 20.32 (in PDF or PS). Deuteron angular distributions have been studied at E(³He) = 9.5 to 21 MeV: see (1978AJ03). See also (1979GR11, 1980MU13; theor.).

40. ¹⁹F(α, t)²⁰Ne Q_m = -6.9694

Angular distributions have been measured at E_α = 18.5 and 28.5 MeV [see (1972AJ02, 1978AJ03)] and at 25.0 MeV (1978LE08; t₀, t₁, t₂). The distributions of the tritons to ²⁰Ne*(0, 1.63, 4.25) have been analyzed by (1974OB02): C²S = 0.08, 0.16 and 0.0 (CCBA) [the DWBA results are nearly the same]. Agreement with the values obtained in the (d, n) and (³He, d) reactions is poor (1974OB02). See also (1979BAYR).

41. ¹⁹F(⁷Li, ⁶He)²⁰Ne Q_m = 2.867

Angular distributions have been studied at E(⁷Li) = 34 MeV for the transitions to ²⁰Ne*(0, 1.63, 4.25, 4.97 (partial), 5.62, 5.78, 6.72, 7.1, 7.42). The spectroscopic factors, C²S, for ²⁰Ne*(0, 1.63, 4.25, 5.78, 6.72, 7.42) are 0.36, 0.54, 0.06, 0.20 and 0.22, respectively, in good agreement with those reported in the (d, n) and (³He, d) reactions (1975WI30).

42. ²⁰F(β^-)²⁰Ne Q_m = 7.0259

The decay is principally to ²⁰Ne*(1.63) with a half-life of 11.00 ± 0.02 sec: see reaction 1 in ²⁰F. Besides the principal decay to ²⁰Ne*(1.63) [log f₀t = 4.97], ²⁰F also decays to ²⁰Ne*(4.97) [J^π = 2^-] with a branching ratio of 0.0090 ± 0.0004% [log f₀t = 7.16 ± 0.02; however the transition is first-forbidden] (1981AL13). The upper limit for the ground-state decay is 0.001% [log f₀t > 10.5] (1978CA02). For other values see Table 20.36 (in PDF or PS) in (1978AJ03). The energy of the γ-ray from ²⁰Ne*(1.63) is 1633.602 ± 0.015 keV (1981WA06). E_γ for the 4.97 → 1.63 transition is 3332.54 (19) keV which gives E_x = 4966.51 (20) keV based on E_x = 1633.674 (15) keV for the first excited state (1981AL13). The shape of the β-spectrum has been measured by (1978CA02) and compared with predictions of the CVC theory: the results are not inconsistent with the predictions of CVC. β - γ correlation measurements lead to an upper limit for the second-class current contribution to the correlation which is consistent with zero (1978DU14, 1978TR07). For the earlier work see (1978AJ03). See also (1982QUZY), (1976BE1E, 1977DE1W, 1978CA1H) and (1976KI1N, 1977OK1A, 1978BE58, 1978CA1H, 1981HO06, 1981KA32; theor.).

43. (a) ²⁰Ne(γ, n)¹⁹Ne Q_m = -16.8653
(b) ²⁰Ne(γ, 2n)¹⁸Ne Q_m = -14.419
(c) ²⁰Ne(γ, p)¹⁹F Q_m = -12.8447
(d) ²⁰Ne(γ, α)¹⁶O Q_m = -4.7309

The photoneutron cross section (bremsstrahlung photons) shows peaks at E_x = 17.78 ± 0.05, 19.00 ± 0.05, 20.15 ± 0.15 [main peak of the GDR], 22.6 ± 0.3, 24.9 ± 0.5 and 27.5 MeV [the latter three states are broad]: the integrated cross section to 28.5 MeV is 58 ± 6 MeV · mb [exhausting ~ 20% of the dipole sum] (1981AL05). The cross section for (γ, Tn) using monoenergetic photons shows a structure at 18 MeV and some fluctuations atop the broad giant resonance, σ_max ~ 7 mb. The double photoneutron cross section, σ(γ, 2n), is dominated by a single peak at ~ 20.5 MeV, σ_max ~ 1.1 mb (1974VE06). For reactions (c) and (d) see (1978AJ03) and reaction 45. See also (1980FL1C; theor.).

44. ²⁰Ne(γ, γ)²⁰Ne

See (1980AC1A, 1981WI1E).

45. (a) ²⁰Ne(e, e)²⁰Ne
(b) ²⁰Ne(e, ep)¹⁹F Q_m = -12.8447
(c) ²⁰Ne(e, eα)¹⁶O Q_m = -4.7309

The ²⁰Ne charge radius, 〈r²〉^1/2 = 3.004 ± 0.025 fm (1981KN07). Form factors for many excited states of ²⁰Ne with E_x < 8 MeV have been reported: see (1978AJ03).

At E_e = 39 and 56 MeV, the 180° inelastic scattering is dominated by the transition to a J^π = 1⁺, T = 1 state at E_x = 11.22 ± 0.05 MeV with Γ_γ₀ = 11.2^+2.1_-1.8 eV. A subsidiary peak is observed corresponding to a state at an E_x = 0.35 ± 0.03 MeV higher [if J^π = 1⁺ or 2⁺, Γ_γ₀ = 0.65 ± 0.18 or 0.40 ± 0.13 eV]. A number of small peaks are also reported corresponding to E_x ~ 12.0, 12.9, 13.9, 15.8, 16.9, 18.0 and 19.0 MeV (1971BE18, and W.L. Bendel, private communication). Prominent electric dipole peaks are reported at E_x = 17.7, 19.1, 20.2 and 23 MeV, in addition to weaker structures between 12.5 and 15 MeV; and prominent electric-quadrupole peaks are observed at E_x = 13.0, 13.7, 14.5, 15.0, 15.4 and 16.2 MeV and there is a broad quadrupole excitation between 16 and 25 MeV (1978SZ02; E_e = 59.5 to 119.7 MeV): the GDR cross section integrated from 11 to 25 MeV contains about 65% of the dipole EWSR while over 90% of the isoscalar quadrupole EWSR is exhausted by the strength in the region 10 - 25 MeV. For reaction (b) see (1978AJ03).

Reaction (c) has been studied in order to obtain the (γ, α₀) cross section in the giant resonance region: the cross section at 90° for E_x = 15 to 24 MeV is dominated by an E1 resonance [1^-; T = 1, with an admixture of T = 0 which permits the α₀ decay] at E_x = 20 MeV; lesser E1 structures are reported at E_x = 16.7, 17.1, 21 and 22 MeV. A relatively strong 2⁺; T = 0 resonance appears at E_x = 18.5 MeV, and evidence is reported for increasing E2 strength below 16 MeV (1975SK06).

See also (1978GU13, 1978HA43, 1978SI11, 1979CH2E, 1979IN06, 1979SI12, 1981ST1B; theor.).

46. ²⁰Ne(n, n)²⁰Ne

See (1978AJ03).

47. (a) ²⁰Ne(p, p)²⁰Ne
(b) ²⁰Ne(p, pα)¹⁶O Q_m = -4.7309
(c) ²⁰Ne(p, 2p)¹⁹F Q_m = -12.8447

Angular distributions of elastically scattered protons and of a number of inelastic groups have been measured for E_p = 2.15 to 41.8 MeV [see (1978AJ03)] and at E_p = 4.5 to 7.9 MeV (1981FE05; p₀), 35.2 MeV (1980FA07; p₀) and E_{pol. p} = 65 MeV (1979SA38; p₀).

Angular distributions at E_p = 24.5 and 30 MeV for the 0⁺, 2⁺ and 4⁺ members of the ground-state K^π = 0⁺ band are well fitted using coupled-channels calculations and deformation parameters of β₂ = +0.47 ± 0.04 and β₄ = +0.28 ± 0.05. When the 6⁺ state is included [²⁰Ne*(8.78)], the fit is improved if β₆ = -0.10 is included: see (1978AJ03).

For yield measurements [p₀, p₁] see (1981FE05). See (1981CA02) for reaction (b). For reaction (c) see (1978AJ03). See also (1981AZ1A), (1979RA1C; astrophys.) and (1977PH02, 1978MA2K, 1979MA01, 1981SM1B; theor.).

48. ²⁰Ne(d, d)²⁰Ne

Angular distributions have been reported at E_d = 10.0 to 52 MeV [see (1978AJ03)] and at E_d = 10 - 12 MeV (1979DA17; d₀, d₁) and 52 MeV (1980MA10; d₀). See also (1979GR11; theor.).

49. ²⁰Ne(t, t)²⁰Ne

See (1978AJ03).

50. ²⁰Ne(³He, ³He)²⁰Ne

Angular distributions have been measured at E(³He) = 10 to 35 MeV and at 68 MeV: see (1978AJ03). See also (1975AU01: S_α) and (1977MA1Y; theor.).

51. (a) ²⁰Ne(α, α)²⁰Ne
(b) ²⁰Ne(α, 2α)¹⁶O Q_m = -4.7309

Angular distributions have been measured at E_α = 3.8 to 155 MeV [see (1978AJ03)], at 21.7 to 23.7 MeV (1982PE1C) and at 25.8, 27.0 and 31.1 MeV (1978CO11; α₀). A coupled-channel analysis of angular distributions at E_α = 104 MeV leads to β₂ = +0.35 ± 0.01, β₄ = +0.11 ± 0.01, Q₂₀ = +0.46 ± 0.02 b and Q₄₀ = +0.026 ± 0.002 b² (1972RE05). At E_α = 155 MeV (1976KN05) find that the strength concentrated in the giant quadrupole resonance exhausts more than 30% of the isoscalar energy-weighted sum rule. See also (1979KN1F).

For yield measurements see (1978AJ03) and (1981DA13). For reaction (b) see (1978AJ03) and (1980WA07; 140 MeV: S_α = 0.202 ± 0.029). See also (1981AN1K), (1979RA1C; astrophys.), (1977MA2E, 1980SP1E, 1980ST1J) and (1978AN20, 1978YO1F, 1979CO15, 1979GO24, 1982BU1D; theor.).

52. ²⁰Ne(⁷Li, ⁷Li)²⁰Ne

Angular distributions have been reported at E(⁷Li) = 36 MeV (1976CO23; g.s.) and 68 and 89 MeV (1979BR03; ²⁰Ne*(0, 1.63)). see also (1979VA1B).

53. (a) ²⁰Ne(¹⁰B, ¹⁰B)²⁰Ne
(b) ²⁰Ne(¹¹B, ¹¹B)²⁰Ne

Elastic scattering angular distributions have been measured at E(¹⁰B) = 65.9 MeV (1979MO14) and E(¹¹B) = 115 MeV (1981GO11).

54. (a) ²⁰Ne(¹²C, ¹²C)²⁰Ne
(b) ²⁰Ne(¹²C, α⁸Be)²⁰Ne Q_m = -7.3667

Elastic angular distributions have been obtained at E(¹²C) = 22.2 to 42.7 MeV [see (1978AJ03)] and 77.4 MeV (1979MO14) and at E(²⁰Ne) = 65.9 MeV (1978DO01) and 74 and 75.2 MeV (1979FO22, 1979SH18; back angles). See also (1980RI1D, 1980SH1T). For yield and fusion measurements see (1978DO01, 1979FO22, 1979SA26, 1979SH18, 1980CO08, 1980HU12, 1980RI1D, 1980SK1A, 1980TS03, 1981DE20, 1981SHZR, 1982DE10). See also (1981VA1E; theor.). For pion production see (1979NA12). For reaction (b) see (1981OS07, 1982DE10). See also (1980MA1T, 1981ST20), (1978RO1L, 1981RO1W; astrophys.), (1979GO1C, 1981SC1J) and (1978TR08, 1978VO06, 1978VO13, 1980OH05, 1981AB1A, 1981AN1D, 1982RA1D; theor.).

55. ²⁰Ne(¹⁶O, ¹⁶O)²⁰Ne

Angular distributions have been studied at E(²⁰Ne) = 50 MeV (1976ST18) and 94.8 MeV (1977MO1A, 1979MO14) involving ¹⁶O_g.s. and ²⁰Ne*(0, 1.63, 4.25). Yield and fusion measurements are reported by (1978GA1G, 1978SH1P, 1979GA1F, 1979GAZY, 1979KOZL, 1979REZS, 1980DI1B, 1980GAZX, 1981GA1D). For pion production see (1981GA1F). See also (1979VA1B, 1981BR1P) and (1979JA11, 1979LE1B, 1980OH05, 1981AN1D, 1982SM1D; theor.).

56. ²⁰Ne(¹⁹F, ¹⁹F)²⁰Ne

See (1979SI1K; theor.).

57. ²⁰Ne(²⁰Ne, ²⁰Ne)²⁰Ne

For yield and fusion measurements see (1978SH1P, 1980DI1B). See also (1979SH22) and (1979CA11, 1979CU1C, 1979PI03, 1979RA06, 1979YA12, 1980BO1J, 1980CU1D, 1981BO11, 1981CU1G, 1981CU1K, 1981JE1B, 1982SM1D; theor.).

58. ²⁰Ne(²⁴Mg, ²⁴Mg)²⁰Ne

Elastic angular distributions have been measured at E(²⁰Ne) = 50, 60, 80, 90 and 100 MeV (1981BE22). For yield and fusion cross sections see (1981BE22, 1981GR08). See also (1980KO46; theor.).

59. ²⁰Ne(²⁷Al, ²⁷Al)²⁰Ne

For yield measurements see (1978OB1B, 1979OBZZ, 1980OB1A, 1981NA07). See also (1978GE08, 1980MA1T, 1981WEZY), (1977SC1G, 1979BE16) and (1979SA10, 1979YA1F; theor.).

60. ²⁰Ne(²⁸Si, ²⁸Si)²⁰Ne

See (1978SA1T, 1979SA10, 1979YA1F; theor.).

61. ²⁰Ne(³²S, ³²S)²⁰Ne

See (1978AJ03).

62. ²⁰Ne(⁴⁰Ca, ⁴⁰Ca)²⁰Ne

Elastic angular distributions are reported at E(²⁰Ne) = 44.1 to 70.4 MeV (1979NG02), 54 and 60.5 MeV (1978NG01; also to ²⁰Ne*(1.63)) and 151 MeV (1980SE06). For yield and fusion measurements see (1978NG01, 1978TRZY, 1979NG02, 1980SE06, 1981KOZS). See also (1979UD02, 1980MA34; theor.).

63. ²⁰Na(β⁺)²⁰Ne Q_m = 13.887

²⁰Na has a half-life of 446 ± 3 msec: see reaction 1 in ²⁰Na. It decays to a number of states of ²⁰Ne, principally ²⁰Ne*(1.63): see Table 20.33 (in PDF or PS). The ratio of the mirror decays ²⁰Na β⁺/→ ²⁰Ne*(1.63) and ²⁰F β^-/→ ²⁰Ne*(1.63), (ft)⁺/(ft)^- = 1.026 ± 0.024 (1973TO08), 1.033 ± 0.022 (1976IN06). β - γ correlation measurements, as in the decay of ²⁰F, lead to an upper limit for the second-class contribution to the correlation which is consistent with zero (1978DU14, 1981TR04). See also (1981CL1D), (1977DE1W, 1977GA1E, 1978AJ03, 1978RA2A) and (1978BE58, 1978CA1H, 1980OK01, 1981HO06; theor.).

64. ²¹Ne(p, d)²⁰Ne Q_m = -4.537

Angular distributions have been measured for d₀ → d₃ at E_p = 14.1 and 20 MeV: see (1978AJ03).

65. ²¹Ne(d, t)²⁰Ne Q_m = -0.504

The T = 1 states observed in this reaction, and the analog states observed in ²⁰F in the (d, ³He) reaction, are displayed in Table 20.15 (in PDF or PS). T = 0 states are presented in Table 20.34 (in PDF or PS).

66. ²¹Ne(³He, α)²⁰Ne Q_m = 13.816

See (1978AJ03) and (1979CO15; theor.).

67. ²²Ne(p, t)²⁰Ne Q_m = -8.644

Angular distributions have been reported at E_p = 26.9 to 43.7 MeV [see (1978AJ03)] and at E_p = 23 MeV (1980AN21; t₀). The angular distributions of the tritons to the ground state of ²⁰Ne and to the first 0⁺, T = 2 state [E_x = 16.722 ± 0.025 MeV (1969HA38)] have been fitted by L = 0 and the tritons to ²⁰Ne*(18.5) by L = 2. The latter is the first 2⁺, T = 2 state. The 0⁺, T = 2 state [²⁰Ne*(16.73)] decays by α₀ [(-6 ± 5)%], α₁ + α₂ [35 ± 12%], α₃ + α₄ [(29 ± 12)%], p₀ + p₁ + p₂ [(14 ± 9)%] and p₃ + p₄ + p₅ [(13 ± 8)%] [measured branching ratios in percent are given in the brackets] to final states in ¹⁶O and ¹⁹F (1970MC04). The ratios of the cross section for formation of the analog states ²⁰Ne*(10.27)/²⁰F*(0) and ²⁰Ne*(12.25 ± 0.03)/²⁰F*(1.85) are 2.00 ± 0.20 and 1.40 ± 0.15, respectively, at E_p = 45 MeV (1969HA19).

At E_p = 40 MeV angular distributions of the tritons to ²⁰Ne(4.97, 5.62, 7.00) [J^π = 2^-, 3^-, 4^-, respectively] have been measured. Coupled-channels calculations reproduce the distributions to the 2^- and 3^- states, but the distribution to the 4^- states cannot be explained entirely in terms of multistep inelastic processes (1975CH17).

68. ²³Na(p, α)²⁰Ne Q_m = 2.377

Angular distributions have been measured at E_p = 10.0 and 45.5 MeV: see (1972AJ02). For yield measurements see (1978AJ03) and (1979KU06). See also (1966YO1A, 1979CH2D) and (1975ZI1A, 1981ZY04; astrophys.).

69. ²³Na(³He, ⁶Li)²⁰Ne Q_m = -1.643

At E(³He) = 40.7 MeV, angular distributions have been measured to ²⁰Ne*(0, 1.63, 4.25) and analyzed using zero-range DWBA (1972OH01).

70. (a) ²⁴Mg(γ, α)²⁰Ne Q_m = -9.3125
(b) ²⁴Mg(p, pα)²⁰Ne Q_m = -9.3125
(c) ²⁴Mg(α, 2α)²⁰Ne Q_m = -9.3125

See (1978AJ03). For reaction (b) see also (1981CA02).

71. ²⁴Mg(d, ⁶Li)²⁰Ne Q_m = -7.839

Angular distributions have been studied to many states of ²⁰Ne at E_d = 28 and 35 MeV [see (1978AJ03)] and at E_d = 28 MeV (1978FO08), 54.25 MeV (1980YA02), 55 MeV (1981VE05) and at 80 MeV (1979OE02, 1980OE01): see Table 20.35 (in PDF or PS). See also (1978BE1H) and (1978TA1F; theor.).