Tunneling and Tunneling Switching Dynamics in Phenol and Its Isotopomers from High‐Resolution FTIR Spectroscopy with Synchrotron Radiation

Abstract

Tunneling and chemical reactions by tunneling switching are reported for phenol and ortho-deuterophenol on the basis of high-resolution FTIR spectroscopy. Tunneling splittings are measured for the torsional motion in the ground and several vibrationally excited states of phenol. Tunneling times range from 10 ns to 1 ps, depending on excitation. For more-highly excited torsional levels in ortho-deuterophenol, delocalization and chemical reaction by tunneling switching is found.

Synchrotron-based highest resolution FTIR spectroscopy of chlorobenzene

“…Our analysis of chlorobenzene's FTIR spectrum is a further extension of our project to understand the dynamics and spectroscopy of aromatic systems. Compared to the complicated FTIR spectra of fluorobenzene [33,41], pyridine [50], pyrimidine [64], indole, naphthalene [3], azulene [8] and phenol [7] the chlorobenzene spectra are relatively easy to understand as long as the lines are resolved. No complicated resonance features have been detected.…”

“…Using the constants in Table 4 The m 10b band of C 6 H 5 35 Cl is not as perturbed as the m 10b band of phenol [7]. All rotational and quartic distortion constants of the m 10b state of C 6 H 5 35 Cl have been determined (Table 4) except the quartic constant D JK which was held fixed at the ground state value.…”

“…The use of synchrotron radiation sources has greatly enhanced the possibilities of highest resolution Fourier Transform Infrared spectroscopy of polyatomic molecules [1][2][3][4][5][6][7][8][9][10][11]. In recent work we have shown that the infrared spectra of molecules as complex as naphthalene [3], azulene [8] and indene [10] can be rotationally resolved and analyzed, which can help the search for the spectra of such molecules in an astrophysical context.…”

“…In recent work we have shown that the infrared spectra of molecules as complex as naphthalene [3], azulene [8] and indene [10] can be rotationally resolved and analyzed, which can help the search for the spectra of such molecules in an astrophysical context. Furthermore tunneling dynamics in excited vibrational states of aromatic molecules such as phenol isotopomers can be studied successfully [7]. Even the spectra of moderately complex chiral molecules such as CDBrClF and CHBrIF and others have been analyzed succesfully [9,11] which provides a starting point for their use in experiments on molecular parity violation [12] which relates to some of the most fundamental current questions on molecular and biomolecular structure and dynamics [13][14][15].…”

“…The vibrational spectrum of chlorobenzene (C 6 H 5 Cl) was assigned in [34][35][36][37]. Although benzene and monodeutero benzene have been studied at high resolution, including work from our group [38][39][40] and recent progress has been made in the analysis of the substituted aromatic molecules phenol [7] and fluorobenzene [33,41], there existed so far only one rovibrational analysis of the m 19a band of chlorobenzene from [42] using diode laser jet spectroscopy. The vibrational ground state has been analyzed using submm wave spectroscopy in [43].…”