| 摘要 |
<p>Optical appts. for measuring circular dichroism in the near ultraviolet (UV) and in UV in vacuo, has a dueterium lamp with max. emission near 2000 angstrongs, supplying a simple monochromator contg. a concave holographic array with no other reflecting element. The beam leaving the monochromator travels through a polariser, a modulator, and then a sample holder, to a photomultiplier which has reduced sensitivity in the visible range of the spectrum. The monochromator pref. uses simple rotation, with fixed inlet and outlet windows, the holographic array providing max. reflected light in UV under vacuum and in the near UV, with no light in the visible range. The deuterium lamp pref. has emission of 1200-3600 angstrongs wavelength, and the appts. operates at 10-6 torr, although the sample holder may contain an inert atmos., e.g. He or N2. Appts. is used in chemistry or biology, e.g. the study of biopolymers and UV absorption bands of cpds.</p> |
