1 CH3Br, C, C* and C** dissociation formation channels vs C+ spectra Explanation for enhanced C+ Rydberg state spectra in the cm-1 region Agust,heima,...Nov09/CH3Br-Overall +mass km ak.pxp Agust,www,.... Nov09/PPT ak.ppt

2 Agust,heima,...Nov09/CH3Br-Overall +mass km ak.pxp: Predictions 2s 2 2p4p( 1 D 2 ): s 2 2p4p( 1 S 0 ): s 2 2p5p: 2s 2 2p6p: H 2 + C + HBr H 2 + C* + HBr ATH! 2hv

3 (1/2)4f;1 (1/2)4f;0+ (3/2)5f;1/0 (3/2)6d;0(1/2)5d;0 (3/2)6d;2(1/2)5d;2 (3/2)6d;0 (1/2)5d;0 (1/2)4f;1 (1/2)4f;0+ (3/2)5f;1/0 agust, heima,....Nov09/CH3Br-Overall +mass km ak.pxp : C+

4 We observe enhanced Rydberg state structure in the spectra region cm-1 by recording C+. This could be for two reasons: 1) -because we switch from three photon ionization of C*(1D) (formed after dissociation of CH3Br*(Rydberg state) to form H2 + C*(1D) + HBr) to two photon ionization. or 2) formation of C**(2s22p2; 1S) due to opening of yet another dissociation channel: CH3Br* -> H2 + C**(2s22p2; 1S) + HBr See relevant energetics in next slides:

cm CH 3 Br 10k 40k 70k CH 3 Br* C*( 1 D 2 )+H 2 +HBr ca C**( 1 D 2 )+H 2 +HBr 130k 150k C + +H 2 +HBr+ e - Ca = = cm-1 80k C ( 3 P J )+ H 2 +HBr ca < 60000(?) (NIST) IP(C) = (see notes ;1)& = cm-1 1)

cm CH 3 Br 10k 40k 70k CH 3 Br* C*( 1 D 2 )+H 2 +HBr ca C**( 1 D 2 )+H 2 +HBr 130k 150k C + +H 2 +HBr+ e - Ca = = cm-1 80k C ( 3 P J )+ H 2 +HBr ca 58952(?) (NIST) IP(C) = (see notes ;1)& = cm-1 2) (alternatively) C*( 1 S)+H 2 +HBr ca (NIST) NB: AB comes up with a value of 704 kJ Mol-1 / cm = (-21.3) for 0 K ( ) I obtain kJmol-1/59329 cm-1 for DE obtained for DHf standard values (see )