Table 4 Calculated average phonon frequencies, electron–phonon coupling constant and superconducting transition temperature from Allen-Dynes formula.

\(\left\langle \omega \right\rangle\)(THz)

5.77

5.74

5.82

\(\left\langle {\omega _{{Li}} } \right\rangle\) (THz)

11.11

11.08

11.20

\(\left\langle {\omega _{{Ga}} } \right\rangle\) (THz)

4.70

4.58

4.65

\(\left\langle {\omega _{{Ir}} } \right\rangle\) (THz)

2.67

2.73

2.78

\(\left\langle {\omega _{{\log }}^{{\alpha ^{2} F}} } \right\rangle\) (THz)

2.22

2.34

2.35

\(\left\langle {\omega _{{\log }}^{{\alpha ^{2} F}} } \right\rangle\)(K)

106.64

112.31

112.69

\(\lambda\)(K)

0.7010

0.6754

0.6708

\(T_{{c,calc}} ({\text{K}})(\mu ^{*} = 0.13)\)

2.85

2.69

2.64

\(T_{{c,calc}} ({\text{K}})(\mu ^{*} = 0.121)\)

3.1053

2.9442

2.8963

\(T_{{c,expt}} ({\text{K}})\)(K)

2.95

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