凡得瓦分子

凡得瓦分子（vdW分子）是鍵結力很弱的分子或原子群，其結合是靠著范德华力或氢键等分子間作用力^[1]。此名詞起源於1970年代，可以用分子束微波光譜（英语：microwave spectroscopy）觀察到穩定的分子簇。

例子编辑

針對一些凡得瓦分子已有相關的研究，例如Ar₂（英语：Diargon）、H₂-Ar、H₂O-Ar、benzene-Ar、(H₂O)₂和(HF)₂。其他的包括最大的雙原子分子氦二聚体和LiHe（英语：LiHe）^[2]^[3]。

超聲束光譜编辑

在（超聲束）分子束中的溫度很低（約低於5 K）。凡得瓦分子在此低溫下會穩定，可以用微波、遠紅外線光譜（英语：far-infrared spectroscopy）及其他光譜偵測到^[4]。在冷平衡氣體中也會形成凡得瓦分子，不過其濃度很小，而且和溫度有關。目前已觀察到氣體中凡得瓦分子的旋轉躍遷和振動躍遷，主要是用紫外以及紅外光譜來觀察。

凡得瓦分子多半是非常的不具剛性，而且可以用很低的能量壁壘分隔出不同的流变分子，因此在遠紅外光譜中看到的穿隧分裂（tunneling splittings）相對較大^[5]。在遠紅外線光譜中可以觀察到凡得瓦分子的分子間振動、旋轉以及穿隧運動（VRT）。凡得瓦分子的VRT光譜研究是目前了解分子间作用力最直接的途徑^[6]。

參考資料编辑

^ Blaney, B L; Ewing, G E. Van Der Waals Molecules. Annual Review of Physical Chemistry. 1976, 27 (1): 553–584. Bibcode:1976ARPC...27..553B. ISSN 0066-426X. doi:10.1146/annurev.pc.27.100176.003005.
^ Friedrich, Bretislav. A Fragile Union Between Li and He Atoms. Physics. 8 April 2013, 6: 42 [2021-08-15]. Bibcode:2013PhyOJ...6...42F. doi:10.1103/Physics.6.42  . （原始内容存档于2017-08-29）.
^ Joshua Jortner. Van der Waals Molecules (Donald Levy). Advances in Chemical Physics, Photoselective Chemistry. John Wiley & Sons. 8 September 2009: 323– [2021-08-15]. ISBN 978-0-470-14313-1. （原始内容存档于2021-08-28）.
^ Smalley, Richard E.; Wharton, Lennard; Levy, Donald H. Molecular optical spectroscopy with supersonic beams and jets. Accounts of Chemical Research. 1977, 10 (4): 139–145 [2021-08-15]. Bibcode:1977mosw.book.....S. ISSN 0001-4842. doi:10.1021/ar50112a006. （原始内容存档于2017-09-23）.
^ Hutson, J M. Intermolecular Forces from the Spectroscopy of Van Der Waals Molecules. Annual Review of Physical Chemistry. 1990, 41 (1): 123–154. Bibcode:1990ARPC...41..123H. ISSN 0066-426X. doi:10.1146/annurev.pc.41.100190.001011.
^ Miller, R. E. Infrared laser photodissociation and spectroscopy of van der Waals molecules. The Journal of Physical Chemistry. 1986, 90 (15): 3301–3313. ISSN 0022-3654. doi:10.1021/j100406a003.

延伸閱讀编辑

So far three special issues of Chemical Reviews have been devoted to vdW molecules: I. Vol. 88(6) (1988). II. Vol. 94(7) (1994). III. Vol. 100(11) (2000).
Early reviews of vdW molecules: G. E. Ewing, Accounts of Chemical Research, Vol. 8, pp. 185-192, (1975): Structure and Properties of Van der Waals molecules. B. L. Blaney and G. E. Ewing, Annual Review of Physical Chemistry, Vol. 27, pp. 553-586 (1976): Van der Waals Molecules.
About VRT spectroscopy: G. A. Blake, et al., Review Scientific Instruments, Vol. 62, p. 1693, 1701 (1991). H. Linnartz, W.L. Meerts, and M. Havenith, Chemical Physics, Vol. 193, p. 327 (1995).

[BlaneyEwing1976-1] Blaney, B L; Ewing, G E. Van Der Waals Molecules. Annual Review of Physical Chemistry. 1976, 27 (1): 553–584. Bibcode:1976ARPC...27..553B. ISSN 0066-426X. doi:10.1146/annurev.pc.27.100176.003005.

[fr13-2] Friedrich, Bretislav. A Fragile Union Between Li and He Atoms. Physics. 8 April 2013, 6: 42 [2021-08-15]. Bibcode:2013PhyOJ...6...42F. doi:10.1103/Physics.6.42  . （原始内容存档于2017-08-29）.

[Jortner2009-3] Joshua Jortner. Van der Waals Molecules (Donald Levy). Advances in Chemical Physics, Photoselective Chemistry. John Wiley & Sons. 8 September 2009: 323– [2021-08-15]. ISBN 978-0-470-14313-1. （原始内容存档于2021-08-28）.

[SmalleyWharton1977-4] Smalley, Richard E.; Wharton, Lennard; Levy, Donald H. Molecular optical spectroscopy with supersonic beams and jets. Accounts of Chemical Research. 1977, 10 (4): 139–145 [2021-08-15]. Bibcode:1977mosw.book.....S. ISSN 0001-4842. doi:10.1021/ar50112a006. （原始内容存档于2017-09-23）.

[Hutson1990-5] Hutson, J M. Intermolecular Forces from the Spectroscopy of Van Der Waals Molecules. Annual Review of Physical Chemistry. 1990, 41 (1): 123–154. Bibcode:1990ARPC...41..123H. ISSN 0066-426X. doi:10.1146/annurev.pc.41.100190.001011.

[Miller1986-6] Miller, R. E. Infrared laser photodissociation and spectroscopy of van der Waals molecules. The Journal of Physical Chemistry. 1986, 90 (15): 3301–3313. ISSN 0022-3654. doi:10.1021/j100406a003.

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Baike

凡得瓦分子

目录

例子编辑

超聲束光譜编辑

相關條目编辑

參考資料编辑

延伸閱讀编辑