C. B. Dane

Color center laser spectroscopy of C2H and C2D

Abstract Gas-phase A 2 Π ← X 2 Σ + electronic transitions of C 2 H and C 2 D have been studied in a discharge through argon over polyacetylene and deuterated polyacetylene by magnetic rotation spectroscopy using a color center laser. The spectra were taken in the infrared region covering the spectral range 3200–3920 cm −1 . One new band of 2 Π ← 2 Σ + symmetry involving the ground vibronic state of C 2 H has been identified and rotationally analyzed. The origin of this band is at 3600 cm −1 . Bands at 3856, 3729, and 3426 cm −1 have been identified and assigned to C 2 D. Rotational analysis of the 3856- and 3426-cm −1 bands has determined that they are both of 2 Π ← 2 Σ + symmetry and that in both cases the lower state is the ground state of the C 2 D radical. The band at 3729 cm −1 has a vibronic symmetry type 2 Σ − ← 2 Π and has been assigned to a hot band of the bending mode with the transition A (0 1 0) ← X (0 1 0) . All four bands were least squares fitted individually with an effective rotational Hamiltonian. The parameters resulting from the fit and the observed frequencies are reported. The effective structure of the linear A state of C 2 H has been determined to be r CC = 1.289 A , r CH = 1.060 A .

Unbiased least-squares fitting of lower states

Abstract An unbiased least-squares method to determine lower state rotational, spin-rotational, and centrifugal distortion constants for vibrational or electronic spectra with perturbed upper states is described. Continuation to fitting procedures for the determination of upper state constants is discussed.

Scaling Demonstration Of The XeF (C->A) Laser

Operation of a scaled, injection-controlled XeF(C→)A) laser is described. The output energy is 0.6 J per pulse from an extracted volume of 0.48 ℓ, which corresponds to an extraction energy density of 125 J/ℓ. The energy deposition in the gas is 105 J/ℓ and the intrinsic efficiency is therefore 1.2%. Also included is the first report of a repetitively-pulsed (1 Hz) electron-beam pumped XeF(C→)A) laser.

Color center laser spesctroscopy of free radicals

High resolution infrared spectra of free radicals are obtained when an electrical discharge occurs through Ar over a coating of polyacetylene. A computer‐controlled color center laser was used as the excitation source. (AIP)

Recent Progress in XeF (C-A) Excimer Laser Technology

The development of the XeF (C-A) eximer laser has been motivated because of its broad wavelength tunability in the visible region which can be utilized for the amplification of ultrashort injection and tunable narrow spectral bandwidth laser pulses.

High Resolution Diode Laser Spectroscopy of Transient Species

An infrared diode laser spectrometer consisting of a tunable diode laser source (Spectra Physics Model SP-5150), an LSI-11/23 microcomputer, alm multipass absorption cell and diagnostic instrumentation to provide frequency markers and reference gas spectra has been constructed in order to study the spectroscopy and kinetics of chemically reactive free radical species. For spectroscopy, these species are produced in the absorption cell from a suitable flowing precursor either by a DC discharge or by excimer laser flash photolysis, while for kinetics studies only the latter method is employed.