In acetylene, C-H stretch occurs about 3300 cm-1. Estimate the position of a C-T stretch.?

In acetylene, C-H stretch occurs about 3300 cm-1. Estimate the position of a C-T stretch. (T=tritium=^3H) (instead of figuring out the reduced masses, it is close enough to just use m for the lighter atom)

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  • 2 months ago
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    From ω=√︎(k/μ) you see that you have to assess how μ changes from CH to CT.

    1/μ = 1/M + 1/mH

    changes to

    1/μ = 1/M + 1/(3mH)

    Therefore the ratio of frequencies becomes

    r = ω=√︎(μT/μH) = ω=√︎3 approximately.

    The wavenumber therefore decreases with a factor √︎3, to 1905 cm-1

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