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A st.udy is made of the experimental consequences of the theory of the vibrational spectra of molecular crystals presented recently in L3]. A discussion is also given of the model used irz this theory. A detailed comparison is made between t.hc theory and experimental resultv for pure and isotropic doped napht.halene crystals in the M-band region. The theory accounts for the decay of electronic-vibrational intra-molecular excitations into pure electronic and intra-molecular vibrational excitations by a resonance interaction. I n this case the crystal spectrum should exhibit a wide absorption band corresponding to two-particle excitation. If the reduction of the vibrational frequencies of the molecule accompanying its electronic excitation is comparable with the pure electronic excitat.ion band width, the spectrum should also show a narrow band corresponding to a one-particle excitation. These bands should be associated with the vibrational band which is observed experimentally. This idea is used to analysis the absorption in t.he first vibrational transition region of a naphthalene crystal. The one-and two-particle excitation regions are identifird and B quantitative analysis of the data is made which is in accordance with the theory. Collect.ive effects, connected with the excitation decay, appear to be important in this transition region. In this connection of particular interest is an analysis of peculiarities of impurity vibrational absorption in isotopic solutions. Comparison between the spectral dat,a naphtalene deutero-isotopes and the theory also indicates the importance of some complicated collective interactions. ann E e T a n 1 , H o r o a r i a J r a a a I I o r a o q e m R R o 6 n a c~~ r~epnoro na6p01111oro Iiepexona H p a c T a m a H a @ T a m i r a , 6bIm B b i A e n e I m 06nac~n o~o -13 X n y x q a c T m a b I x ~0 3 -6 y ) I i Z C H H P H r I p o i , e ; I e I I a 0 6 p a 6 O T I i a j a r r m I x R COOTBCTCTBAA c T C O~A C~~. O B I r a p y -

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