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Acetylene excited state geometry

Acetaldehyde, 119-20, 380-82 Acetone, chemical titration. 428 oxetane formation, 318, 427 singlet and triplet states, 382. 428 Acetophenone. 407. 467 Acetylene, 203. 348 cycloaddition, 415, 423 excited state geometry. 45-46 2-Acetylnaphthalene, 398 6-Acetyloxycyclohexadienones. 463 Acidity, excited states, 48-52 Acrolein, 34, 382-83, 433 Acrylonitrile, 328, 414-15, 417 Activation energy, 382-83, 400 Acyl radical. 3S2-S5, 380-82, 460 Adiabatic. See Potential energy surface ... [Pg.272]

Van der Waals complexes were observed between two molecules of 1,2,4,5-tetrazine (la) and helium, argon, krypton, xenon, hydrogen, water, hydrochloric acid, acetylene or benzene 28 36- 396-420 jn coi,j environment of a jet expansion. In favorable systems it has been possible to determine the ground and excited state geometry of the cluster by laser spectroscopy. From these structures, it has been found that 1,2,4,5-tetrazine possesses a number of different binding sites. Helium and argon bind to the equivalent sites above and below the ring.28-30 The predominant interaction in these clusters is presumably the attractive dispersion force. [Pg.872]

The properties of excited states are not easy to measure because of their generally short lifetimes and low concentrations, but enough work has been done for us to know that they often differ from the ground state in geometry, dipole moment, and acid or base strength. For example, acetylene, which is linear in the ground state, has a trans geometry... [Pg.311]

Interestingly, after reaching the maximum at the 6-membered cycle, the yields drop again. This decrease in efficiency occurs despite the appreciable reduction in the distance between the terminal acetylenic carbons relative to the 6-membered analogue. Here, the efficiency may simply be a function of how photochemical excitation is distributed in the reactive excited state. Calculated enediyne geometries suggest the cyclization is more efficient for those enediynes where the terminal phenyl groups are rotated outside of the enediyne plane (Table 3). [Pg.28]

Following his self-consistent field MO calculations on acetylene, Burnelle (1964) examined the role of excited states and molecular vibrations in determining 88 of additions. He found that, when a proton is brought close to acetylene, the energy of the trans-hent structure falls below that of the linear form. For similar addition to ethylene, Bumelle (1965) found that the first stable intermediate derived from the 90° twisted form of ethylene. Since such a geometry could only lead to SS = 0—there is no preferred orientation for attack— this particular model was less successful for ethylene than for acetylene. [Pg.294]

Figure 5.14. Geometry of (a) ground and (b) first excited singlet states of acetylene. Figure 5.14. Geometry of (a) ground and (b) first excited singlet states of acetylene.
Figure 1.9 Geometry of tai the lowest tit.tt ) excited singlet state ol ethylene, ib) the lowest tJi.n ) excited singlet state of acetylene, and (c) the lowest in. n l state of formaldehyde... Figure 1.9 Geometry of tai the lowest tit.tt ) excited singlet state ol ethylene, ib) the lowest tJi.n ) excited singlet state of acetylene, and (c) the lowest in. n l state of formaldehyde...

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See also in sourсe #XX -- [ Pg.245 , Pg.246 , Pg.247 , Pg.248 , Pg.249 ]

See also in sourсe #XX -- [ Pg.245 , Pg.246 , Pg.247 , Pg.248 , Pg.249 ]




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