Condensed values of mean and amplitudes of vibration

CHEMICAL

PHYSICS

LETTERS

CONDENSED

1 (1967)

211-213.

NORTH - HOLLAND

PUBLISHING

VALUES OF MEAN AMPLITUDES

Institute

COiWPANi

,

.kMSTERD-M

OF VIBRATION

B. N. CYVIN, S. J. CYVTN and G. BAGEN of Physical Chemistq, Tecknicat Univevsifs of Norway, Trondheim , Norrcajr Received 15 June 1967

Calculated mean amplitudes of @bration for all types of distances in light and heavy taphthakne and benzene are represcsted (in IO-3 .Aunits) on figures. Some comments are made on the partially deuterated compounds.

In this communication we present the mean amplitudes of vibration for naphthalene from spectroscopic calculations. Fig. 1 shows the results for most of the CC distances (solid lines) and several CH distances (broken lines), with the CD values in parentheses. Fig. 2 shows the values for the rest of the CC distances, and additional CE or CD distances. Finally, fig. 3 shows the results for the rest of the CH or CD distances (broken lines), and all HH distances (solid lines), with the DD values included in parentheses. The reported values may be applied (within the given numbers of decimals) to all deuterated naphthalenes. Only the BD mean amplitudes are not found here, but they fall inbetween the corresponding HH and DD values.

Fig.

1. Mean amplitudes

of vibration

All the here reported results pertain to the temperature of 298oK. The data presented in figs. 1-3 have been condensed from calculations for naphthalene, naphthalene-da, and several (not al) partial.ly deuterated naphthdenes. The results are beLieved to be of particular interest for workers in gas electron diffraction. As a matter of fact naphthalene is one of the molecules acfxaUy investigated by this method [I]. The mean amplitudes of vibration for benzene and benzene-d6 have been calculated several times. Recently the computations were extended to include all types of partially deuterated benzenes [2]. The cited reference [2] contains a summary of the previous work, both from elec-

(in 10 -3 A) for naphthalene and deuterated naphthalenes CC, and CH or CD (in parentheses) distances.

at 2980K. Valles

for

212

I

B. N. CYVIN,

S. J. CYVIN

and G. HAGEN

Fig. 2. (Top) Mean amplitudes of vibration (in 10e3 A) for naphthalene and deuterated naphthalenes at 29801;. Values for CC, and CH or CD (in parentheses) distances.

Fig. 3, (Middle) Mean amplitudes of vibration (in 10-8 A) for naphthalene and deuterated naphth‘alenes at 2980K. Values for CH or CD (in parentheses), and HH or DD (in parentheses) distances.

Fig. %_ (Bottom) Mean amplitudes of vibratfon (in 10-8 A) for benzene and deuterated benzenes at 298OK. Values for CD (broken lines) and DD (solid linos) distances’given in parentheses.

CONDENSED

VALUES

OF MEAN

tron dtffraction and spectroscopic calculations. Fig. 4 shows the calculated mean amplitudes (in 10m3i) for all types of distances in benzene. A more detailed account on the mean amplitudes of vibration in deuterated benzenes will be found in the cited book [2] when published. The present data of benzene mean amplitudes are communicated here primarily to make them easily accessible for comparison with the similar data on naphthalenes discussed above.

AMPLITUDES

OF VIBRATION

213

REFERENCES [l]

A. Almenningen. 0. Bastiansen and F. Dyvik. Acta Cry&. 14 (1961) 1056. [2] S. J. Cyvin. Molecular Vibrations and Mean Square Amplitudes (ZJniversitetsforIaget, 0~10). to be published.