TY - JOUR

T1 - Why computed entropies of quasi-linear species are sometimes random?

AU - Slanina, Zdeněk

AU - Martin, Jan M.L.

AU - François, Jean Pierre

AU - Adamowicz, Ludwik

N1 - Funding Information:
The authorst hankthe National Fund for Scientific Researcho f Belgium (NFWO/FNRS) for a computert ime grant. J.M.L.M. thanks the same institutionf or a senior researcha ssistants cholar-ship.T his paperf orms a part of ther esearchre sults of a programi n Inter-universityA ttraction Poles, initiatedb y the Belgians tateP rime Minister’so ffice sciencep olicy programming.

PY - 1993/3/11

Y1 - 1993/3/11

N2 - Using the example of a gaussian 90 computation of the linear BBNB molecule in its singlet state, it is shown that the calculated entropy value can be considerably different from that deduced from seemingly equivalent computations performed on a quasi-linear species. This problem is interpreted in terms of the limiting behaviour of the conventional rotational partition function of a polyatomic molecule. The problems originate from a routine application of quantum-chemical programs to such linear cases. The results are shown to be important for linear systems optimized (owing to, for example, better convergence properties) as quasi-linear systems. The finding explains why some published computed entropies of essentially linear species cannot be reproduced.

AB - Using the example of a gaussian 90 computation of the linear BBNB molecule in its singlet state, it is shown that the calculated entropy value can be considerably different from that deduced from seemingly equivalent computations performed on a quasi-linear species. This problem is interpreted in terms of the limiting behaviour of the conventional rotational partition function of a polyatomic molecule. The problems originate from a routine application of quantum-chemical programs to such linear cases. The results are shown to be important for linear systems optimized (owing to, for example, better convergence properties) as quasi-linear systems. The finding explains why some published computed entropies of essentially linear species cannot be reproduced.

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U2 - 10.1016/0166-1280(93)87096-V

DO - 10.1016/0166-1280(93)87096-V

M3 - Article

AN - SCOPUS:44949267530

VL - 280

SP - 83

EP - 87

JO - Computational and Theoretical Chemistry

JF - Computational and Theoretical Chemistry

SN - 2210-271X

IS - 1

ER -