File Download
  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Early-time photodissociation dynamics of chloroiodomethane in the A-band absorption from resonance Raman intensity analysis

TitleEarly-time photodissociation dynamics of chloroiodomethane in the A-band absorption from resonance Raman intensity analysis
Authors
KeywordsPhysics chemistry
Physical chemistry
Issue Date1996
PublisherAmerican Institute of Physics. The Journal's web site is located at http://jcp.aip.org/jcp/staff.jsp
Citation
Journal Of Chemical Physics, 1996, v. 104 n. 24, p. 9816-9832 How to Cite?
AbstractWe have obtained resonance Raman spectra and absolute Raman cross sections for h 2-chloroiodomethane (fourteen excitation wavelengths between 200 nm and 355 nm) and d 2-chloroiodomethane (for 282.4 nm excitation) in cyclohexane solution. Most of the intensity in the A-band resonance Raman spectra appears in the nominal C-I stretch overtones progression and combination bands of the nominal C-I stretch overtones with the fundamentals of the CH 2 wag, CH 2 scissor, and the Cl-C-I bend or C-Cl stretch fundamentals. The A-band absorption and absolute resonance Raman intensities were simulated using a simple model which included preresonant contributions to the fundamental Raman peaks and time-dependent wave packet calculations. The motion of the wave packet on the excited state surface was converted from dimensionless normal coordinates into internal coordinates using the results of normal coordinate calculations. The A-band short-time photodissociation dynamics of chloroiodomethane shows that the C-I bond lengthens, the I-C-Cl and H-C-I angles become smaller, and the H-C-Cl angles become larger. These internal coordinate motions which are associated with relatively low frequency modes are consistent with a simple impulsive "soft" radical model of the photodissociation and the CH 2Cl group changing to a more planar structure. However, the C-H bond length does not change much and the H-C-H angle (associated with higher frequency modes) becomes slightly smaller which is inconsistent with the "soft" radical model and the CH 2Cl group changing to a more planar structure. This suggests that an impulsive "semirigid" radical model may be more appropriate than the "soft" radical model to qualitatively describe the chloroiodomethane photodissociation. An ambiguity in the assignment of the 724 cm -1 Raman peak and its associated combination bands to combination bands of the nominal C-I stretch overtones with the fundamentals of the Cl-C-I bend or C-Cl stretch fundamentals limits what we are able to determine about the C-Cl bond length changes during the initial stages of the photodissociation. © 1996 American Institute of Physics.
Persistent Identifierhttp://hdl.handle.net/10722/42340
ISSN
2015 Impact Factor: 2.894
2015 SCImago Journal Rankings: 0.959
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorKwok, WMen_HK
dc.contributor.authorPhillips, DLen_HK
dc.date.accessioned2007-01-29T08:47:20Z-
dc.date.available2007-01-29T08:47:20Z-
dc.date.issued1996en_HK
dc.identifier.citationJournal Of Chemical Physics, 1996, v. 104 n. 24, p. 9816-9832en_HK
dc.identifier.issn0021-9606en_HK
dc.identifier.urihttp://hdl.handle.net/10722/42340-
dc.description.abstractWe have obtained resonance Raman spectra and absolute Raman cross sections for h 2-chloroiodomethane (fourteen excitation wavelengths between 200 nm and 355 nm) and d 2-chloroiodomethane (for 282.4 nm excitation) in cyclohexane solution. Most of the intensity in the A-band resonance Raman spectra appears in the nominal C-I stretch overtones progression and combination bands of the nominal C-I stretch overtones with the fundamentals of the CH 2 wag, CH 2 scissor, and the Cl-C-I bend or C-Cl stretch fundamentals. The A-band absorption and absolute resonance Raman intensities were simulated using a simple model which included preresonant contributions to the fundamental Raman peaks and time-dependent wave packet calculations. The motion of the wave packet on the excited state surface was converted from dimensionless normal coordinates into internal coordinates using the results of normal coordinate calculations. The A-band short-time photodissociation dynamics of chloroiodomethane shows that the C-I bond lengthens, the I-C-Cl and H-C-I angles become smaller, and the H-C-Cl angles become larger. These internal coordinate motions which are associated with relatively low frequency modes are consistent with a simple impulsive "soft" radical model of the photodissociation and the CH 2Cl group changing to a more planar structure. However, the C-H bond length does not change much and the H-C-H angle (associated with higher frequency modes) becomes slightly smaller which is inconsistent with the "soft" radical model and the CH 2Cl group changing to a more planar structure. This suggests that an impulsive "semirigid" radical model may be more appropriate than the "soft" radical model to qualitatively describe the chloroiodomethane photodissociation. An ambiguity in the assignment of the 724 cm -1 Raman peak and its associated combination bands to combination bands of the nominal C-I stretch overtones with the fundamentals of the Cl-C-I bend or C-Cl stretch fundamentals limits what we are able to determine about the C-Cl bond length changes during the initial stages of the photodissociation. © 1996 American Institute of Physics.en_HK
dc.format.extent250559 bytes-
dc.format.extent30208 bytes-
dc.format.mimetypeapplication/pdf-
dc.format.mimetypeapplication/msword-
dc.languageengen_HK
dc.publisherAmerican Institute of Physics. The Journal's web site is located at http://jcp.aip.org/jcp/staff.jspen_HK
dc.relation.ispartofJournal of Chemical Physicsen_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subjectPhysics chemistryen_HK
dc.subjectPhysical chemistryen_HK
dc.titleEarly-time photodissociation dynamics of chloroiodomethane in the A-band absorption from resonance Raman intensity analysisen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0021-9606&volume=104&issue=24&spage=9816&epage=9832&date=1996&atitle=Early-time+photodissociation+dynamics+of+chloroiodomethane+in+the+A-band+absorption+from+resonance+Raman+intensity+analysisen_HK
dc.identifier.emailPhillips, DL:phillips@hku.hken_HK
dc.identifier.authorityPhillips, DL=rp00770en_HK
dc.description.naturepublished_or_final_versionen_HK
dc.identifier.doi10.1063/1.471741en_HK
dc.identifier.scopuseid_2-s2.0-0000365858en_HK
dc.identifier.hkuros21549-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0000365858&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume104en_HK
dc.identifier.issue24en_HK
dc.identifier.spage9816en_HK
dc.identifier.epage9832en_HK
dc.identifier.isiWOS:A1996UR69200016-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridKwok, WM=7103129332en_HK
dc.identifier.scopusauthoridPhillips, DL=7404519365en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats