• Quartic force fields of the highest level provide rotational constants to within, on average, 34 MHz experiment. Tetraatomic species with low anharmonicities can be within 20 MHz. These same methods vibrational frequencies 5.8 cm ?1 . The CcCR quartic field (QFF) methodology is capable computing B 0 and C 35 (0.14%) experiment for triatomic larger molecules at least two heavy atoms. Additiona...

BACKGROUND In many songbirds the larger vocal repertoire of males is associated with sexual dimorphism of the vocal control centers and muscles of the vocal organ, the syrinx. However, it is largely unknown how these differences are translated into different acoustic behavior. METHODOLOGY/PRINCIPAL FINDINGS Here we show that the sound generating structures of the syrinx, the labia and the ass...

The interstellar presence of protonated nitrous oxide has been suspected for some time. Using established high-accuracy quantum chemical techniques, spectroscopic constants and fundamental vibrational frequencies are provided for the lower energy O-protonated isomer of this cation and its deuterated isotopologue. The vibrationally-averaged B0 and C0 rotational constants are within 6 MHz of thei...

In this paper, a method for extracting fundamental frequencies (F0s) from single channel input signal of concurrent sounds is described. By considering that an observed spectral density distribution is a statistical distribution of (imaginary) micro-energies, we attempt to classify them into each sound by the use of clustering principle. We call this approach a “Harmonic Clustering.” One of the...

The vibration spectra of hydrazoic acid, methyl azide, and methyl isocyanate have been investigated in the spectral region between 2 and 20~. Correlation of the spectra of these structurally similar molecules has made possible the determination of all the fundamental frequencies of hydrazoic acid and all but the methyl torsion frequency in the methyl compounds. From these fundamental frequencie...

Exterior boundary-value problems for the Helmholtz equation can be reduced to boundary integral equations. It is known that the simplest of these fail to be uniquely solvable at certain ‘irregular frequencies.’ For a single smooth scatterer, it is also known that irregular frequencies can be eliminated by using a modified fundamental solution, one that has additional singularities inside the sc...

In this paper, we propose a novel method for detecting the fundamental frequencies of speech signals contaminated by noise. The proposed method exploits an eigen-based subspace principle to estimate unknown parameters of the noisy speech signal. In the proposed method, the estimated parameters are used for recovering the spectrum of the signal buried in noise, and then the restored spectrum is ...