Measurement of infrared spectroscopy has emerged as a significant challenge for carbon materials due to the sampling problem. To overcome this issue, in this work, we performed measurements of IR spectra for carbon materials including C₆₀, C₇₀, diamond powders, graphene, and carbon nanotubes (CNTs) using the photoacoustic spectroscopy (PAS) technique; for comparison, the vibrational patterns of these materials were also studied with a conventional transmission method, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, or Raman spectroscopy. We found that the IR photoacoustic spectroscopy (IR-PAS) scheme worked successfully for these carbon materials, offering advantages in sampling. Interestingly, the profiles of IR-PAS spectra for graphene and CNTs exhibit negative bands using carbon black as the reference; the negative spectral information may provide valuable knowledge about the storage energy, production, structure, defect, or impurity of graphene and CNTs. Thus, this approach may open a new avenue for analyzing carbon materials.

Cross sections for photoabsorption of $\mathrm{N}{\mathrm{H}}_3$ , $\mathrm{N}{\mathrm{H}}_2\mathrm{D}$ , $\mathrm{N}\mathrm{H}{\mathrm{D}}_2$ , and $\mathrm{N}{\mathrm{D}}_3$ near $298\mathrm{K}$ were measured in the spectral range of $110–144\mathrm{nm}$ using radiation from a synchrotron. Absorption cross sections and oscillator strengths of $\mathrm{N}{\mathrm{H}}_3$ agree satisfactorily with previous reports; those of $\mathrm{N}{\mathrm{D}}_3$ are improved over those in a previous report, whereas those of $\mathrm{N}{\mathrm{H}}_2\mathrm{D}$ and $\mathrm{N}\mathrm{H}{\mathrm{D}}_2$ are new. The oscillator strengths of transitions to $D$ , $D^{\prime }$ , $D^{″}$ , $F$ , and $G$ states are nearly the same among all four isotopic variants, but those to $D^{‴}$ and $E$ states vary substantially. Observed absorption bands are arranged into vibrational progressions in accord with known Rydberg transitions. All progressions show a common trend of vibrational intervals increasing with vibrational quantum numbers. The Rydberg orbitals for states $D\left(3d{e}^{″}\right)$ , $D^{\prime }\left(4sa_1{}^{\prime }\right)$ , $D^{″}\left(3da_1{}^{\prime }\right)$ , $D^{‴}\left(4p{e}^{\prime }\right)$ , and $E\left(4d{e}^{″}\right)$ are readily assigned with quantum defects determined in these experiments, but assignments for $F\left(5d{e}^{″}\right)$ and $G\left(6d{e}^{″}\right)$ are uncertain. Absorption cross sections of dissociative continua underneath discrete structures are larger for $\mathrm{N}{\mathrm{H}}_2\mathrm{D}$ and $\mathrm{N}\mathrm{H}{\mathrm{D}}_2$ than for $\mathrm{N}{\mathrm{H}}_3$ and $\mathrm{N}{\mathrm{D}}_3$ , indicating that the rate of dissociation of ammonia might increase when its symmetry is broken.

Urinary tract infections (UTIs) are a leading hospital-acquired infection. Although timely detection of causative pathogens of UTIs is important, rapid and accurate measures assisting UTI diagnosis and bacterial determination are poorly developed. By reading infrared spectra of urine samples, Fourier-transform infrared spectroscopy (FTIR) may help detect urine compounds, but its role in UTI diagnosis remains uncertain. In this pilot study, we proposed a characterization method in attenuated total reflection (ATR)-FTIR spectra to evaluate urine samples and assessed the correlation between ATR-FTIR patterns, UTI diagnosis, and causative pathogens. We enrolled patients with a catheter-associated UTI in a subacute-care unit and non-UTI controls (total n = 18), and used urine culture to confirm the causative pathogens of the UTIs. In the ATR-FTIR analysis, the spectral variation between the UTI group and non-UTI, as well as that between various pathogens, was found in a range of 1800–900 cm⁻¹, referring to the presence of specific constituents of the bacterial cell wall. The results indicated that the relative ratios between different area zones of vibration, as well as multivariate analysis, can be used as a clue to discriminate between UTI and non-UTI, as well as different causative pathogens of UTIs. This warrants a further large-scale study to validate the findings of this pilot research.