Consider positronium, an atomic-like system made of an electron and a positron. Find the wavelengths for the transitions n=2 --> 1 and n=3 --> 1. Compare each to the similar transitions for hydrogen.
Consider positronium, an atomic-like system made of an electron and a positron. Find the wavelengths for the transitions n=2 --> 1 and n=3 --> 1. Compare each to the similar transitions for hydrogen.
Reduced mass of positronium, u = mm/m+m = m2/2m = m/2
where m is mass of electron or positron
wavelengths for the transitions n=2 --> 1,
1/ = RH (1/n2i - 1/n2f)
ni = 2 and nf = 1
1/ = RH (1/22 - 1/12) = RH (1/4 - 1/1) = RH ((4-1)/4) = RH (3/4)
= 4/3RH
RH = (R/me) x u
where R is Rydberg constant for Hydrogen = 1.097 x 107 m
RH = R/me x m/2 = R/2 = 1.097 x 107 m/2 = 0.5485 x 107 m
= 4/3RH = 4 / 0.5485 x 107 mx3 = 4/1.6455 x 107 = 2.431 x 10-7 m = 243.1 x 10-9 m = 243.1 nm
wavelengths for the transitions n=3 --> 1,
1/ = RH (1/n2i - 1/n2f)
ni = 3 and nf = 1
1/ = RH (1/32 - 1/12) = RH (1/9 - 1/1) = RH ((9-1)/9) = RH (8/9)
= 9/8RH
RH = (R/me) x u
where R is Rydberg constant for Hydrogen = 1.097 x 107 m
RH = R/me x m/2 = R/2 = 1.097 x 107 m/2 = 0.5485 x 107 m
= 9/8RH = 9 / 0.5485 x 107 mx8 = 9/4.388 x 107 = 2.051 x 10-7 m = 205.1 x 10-9 m = 205.1 nm
Step by step
Solved in 2 steps