In:
The Journal of Chemical Physics, AIP Publishing, Vol. 141, No. 4 ( 2014-07-28)
Kurzfassung:
Through the study of the C3(${\tilde X}$X̃1Σg+) + He(1S) astrophysical relevant system using standard (CCSD(T)) and explicitly correlated (CCSD(T)-F12) coupled cluster approaches, we show that the CCSD(T)-F12/aug-cc-pVTZ level represents a good compromise between accuracy and low computational cost for the generation of multi-dimensional potential energy surfaces (PESs) over both intra- and inter-monomer degrees of freedom. Indeed, the CCSD(T)-F12/aug-cc-pVTZ 2D-PES for linear C3 and the CCSD(T)-F12/aug-cc-pVTZ 4D-PES for bent C3 configurations gently approach those mapped at the CCSD(T)/aug-cc-pVXZ (X = T,Q) + bond functions level, whereas a strong reduction of computational effort is observed. After exact dynamical computations, the pattern of the rovibrational levels of the intermediate C3–He complex and the rotational and rovibrational (de-) excitation of C3 by He derived using both sets of PESs agree quite well. Since C3 shows a floppy character, the interaction PES is defined in four dimensions to obtain realistic collisional parameters. The C–C–C bending mode, which fundamental lies at 63 cm−1 and can be excited at very low temperatures is explicitly considered as independent coordinate. Our work suggests hence that CCSD(T)-F12/aug-cc-pVTZ methodology is the key method for the generation of accurate polyatomic – He/H2 multi-dimensional PESs.
Materialart:
Online-Ressource
ISSN:
0021-9606
,
1089-7690
Sprache:
Englisch
Verlag:
AIP Publishing
Publikationsdatum:
2014
ZDB Id:
3113-6
ZDB Id:
1473050-9
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