# ``d15n_alpha_n2o``
## Properties
:dimensions: N_PROF, N_LEVELS
:dtype: float64
## Default Attributes
| Attribute | Value |
|-----|-----|
|``whp_name`` | ``D15N_ALPHA_N2O`` |
|``whp_unit`` | ``/MILLE`` |
|``units`` | ``1e-3`` |
|``C_format`` | ``%9.1f`` |
|``C_format_source`` | ``database`` |
## Description
Enrichment of :sup:`15`\ N vs :sup:`14`\ N in N2O (nitrous oxide) where the substitution has occurred at the center position of the N2O molecule as compared to a standard. N2O where the substitution has occurred in the end nitrogen atom is called D15N_BETA and is not usually measured. D15N_BETA can be calculated from bulk D15N and D15N_ALPHA using equation 25 from Toyoda and Yoshida 1999 [Toyoda1999]_

.. math::

    \delta^{15}\text{N}^\beta = \delta^{15}\text{N}^\text{bulk} + A( \delta^{15}\text{N}^\text{bulk} -  \delta^{15}\text{N}^\alpha)/(2-A)

Toyoda and Yoshida give the value of A=0.998, though this needs to be determined experimentally for the standard in use. We have seen data using a value of A=1 in data submitted to CCHDO.

.. [Toyoda1999] Determination of Nitrogen Isotopomers of Nitrous Oxide on a Modified Isotope Ratio Mass Spectrometer; Sakae Toyoda and Naohiro Yoshida; Analytical Chemistry 1999 71 (20), 4711-4718; DOI: 10.1021/ac9904563