ˈɔːlsoʊ nˈoʊt ðæt ðæt ˈɪz, ðə pˈɛɹ ˈɛnɚdʒi bᵻtwˌiːn ɐ ɹˈoʊɾeɪmɚ ænd ɪtsˈɛlf ɪz tˈeɪkən təbi zˈiəɹoʊ, ænd ðˈʌs dʌznˌɑːt ɐfˈɛkt ðə sʌmˈeɪʃənz.
Also note that  (that is, the pair energy between a rotamer and itself) is taken to be zero, and thus does not affect the summations.