{"id":391007,"date":"2025-03-06T01:00:00","date_gmt":"2025-03-06T07:00:00","guid":{"rendered":"http:\/\/www.r-bloggers.com\/?guid=f614795091f442d970e99b1ec54377c6"},"modified":"2025-03-06T01:00:00","modified_gmt":"2025-03-06T07:00:00","slug":"a-function-to-draw-complex-multiplets","status":"publish","type":"post","link":"https:\/\/www.r-bloggers.com\/2025\/03\/a-function-to-draw-complex-multiplets\/","title":{"rendered":"A Function to Draw Complex Multiplets"},"content":{"rendered":"\r\n\r\n
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Inspired by Roman A. Valiulin\u2019s<\/a> book NMR Multiplet Interpretation<\/a> (discussed previously<\/a>), I decided to write an R<\/code> function to draw complex multiplets. The function will draw the multiplet, and optionally, can draw a splitting tree and some annotations.1<\/sup> Some of you may find this useful for teaching the topic.<\/p>\n

The function is called multiplet<\/code> and it resides in the SpecHelpers<\/code> package<\/a>, which was just updated to version 0.3.1. Here are some examples of the function at work, drawn from Valiulin\u2019s book:<\/p>\n

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library("SpecHelpers") # you need version 0.3.1<\/pre>\n<\/div>\n
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# Example 3.1 from Valiulin, a ddt.\nres <- multiplet(J = c(16.8, 10.1, 6.7, 6.7))<\/pre>\n
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# Example 3.2 from Valiulin, a tt.\nres <- multiplet(J = c(6.1, 6.1, 2.15, 2.15))<\/pre>\n
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# Example 3.3 from Valiulin, a dddd.\nres <- multiplet(J = c(12.7, 12.2, 10.0, 4.9))<\/pre>\n
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One interesting aspect of Valiulin\u2019s approach is that all multiplets are treated as doublets of doublets \u2026 of doublets. We can use the new function to show how a triplet can be understood as a doublet of doublets in which the coupling constants are the same. Starting from what is clearly a doublet of doublets we can see how the spectrum changes as the coupling constants become more equal, finally leading to the overlap of the two central peaks, giving a triplet.<\/p>\n
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Jvals <- c(2, 4, 8, 10, 11, 12)\nfor (i in 1:length(Jvals)) {\n  res <- multiplet(J = c(12, Jvals[i]), pw = 0.25)\n}<\/pre>\n
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I hope some of you will find this function useful!<\/p>\n\n\n\n\n