Question

Estimate the the lifetime of a state that gives rise to a line of a width (a) 0.2 cm⁻¹ and (b) 2.0 cm⁻¹.

Answer 1

(a) lifetime of a state = h/2.pi.dE

with,

dE = hc.l

l = line width

h = planck's constant

c = 3.0 x 10^10 cm/s

For, l = 0.2 cm-1

we get,

lifetime of a state = 6.626 x 10^-34/(2 x 3.14 x 6.626 x 10^-34 x 3 x 10^10 x 0.2)

                            = 2.65 x 10^-11 s

(b) Similarly, when l = 2.0 cm-1

lifetime of a state = 6.626 x 10^-34/(2 x 3.14 x 6.626 x 10^-34 x 3 x 10^10 x 2.0)

                            = 2.65 x 10^-12 s