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Working with molecules in first excited rotational state

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Calculate the ratio of HCL molecules in the first excited rotational state to those in the ground state @ 25 C. Assume an equilibrium bond distance of 1.275 angstroms.

the angstrom part of the problem throws me off, I usually start these out by solving Change in E = ( h ) ( c )(Wo), but this is a q (rot) prob, not a q (elec). how do i solve this ?

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If we have No molecules in the gnd state and Nj atoms in the excited state, , the boltzmann distribution tells us that,

Nj/No = Exp[-Ej/kT]

where K = 1.38*10^-23, the Boltzmann's constant, T is the absolute temperature and Ej is given by,

Ej = BhC J(J+1)

where h = 6.63*10^-34 JS, the Planks constant
C the velocity of licht in cm/second
and B is the rotational ...

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Populated Rotational State as a Function of Temperature

Using the Boltzmann distribution given below, determine Jmax (quantum number of the most intensely populated rotational state) as a function of temperature. Then find Jmax for CN+ at 298 K and 1100 K.
and CN+ bond length is 0.129 nm
the Boltzman distribution: (Ni/N)= (exp(-ei/KT))/(sigma j exp(-Ej/KT)).

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